change #include "binarybuffer.h" to <helper/binarybuffer.h>
[fw/openocd] / src / target / armv4_5.c
index 413061fcf7532f9be922a8d0b13f332464bd9cc0..80c06ef31d355a7c4f5f523b928935a4066ea06c 100644 (file)
 #include "arm_jtag.h"
 #include "breakpoints.h"
 #include "arm_disassembler.h"
-#include "binarybuffer.h"
+#include <helper/binarybuffer.h>
 #include "algorithm.h"
 #include "register.h"
 
 
-char* armv4_5_core_reg_list[] =
-{
-       "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r13_usr", "lr_usr", "pc",
+/* offsets into armv4_5 core register cache */
+enum {
+//     ARMV4_5_CPSR = 31,
+       ARMV4_5_SPSR_FIQ = 32,
+       ARMV4_5_SPSR_IRQ = 33,
+       ARMV4_5_SPSR_SVC = 34,
+       ARMV4_5_SPSR_ABT = 35,
+       ARMV4_5_SPSR_UND = 36,
+       ARM_SPSR_MON = 39,
+};
+
+static const uint8_t arm_usr_indices[17] = {
+       0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, ARMV4_5_CPSR,
+};
 
-       "r8_fiq", "r9_fiq", "r10_fiq", "r11_fiq", "r12_fiq", "r13_fiq", "lr_fiq",
+static const uint8_t arm_fiq_indices[8] = {
+       16, 17, 18, 19, 20, 21, 22, ARMV4_5_SPSR_FIQ,
+};
 
-       "r13_irq", "lr_irq",
+static const uint8_t arm_irq_indices[3] = {
+       23, 24, ARMV4_5_SPSR_IRQ,
+};
 
-       "r13_svc", "lr_svc",
+static const uint8_t arm_svc_indices[3] = {
+       25, 26, ARMV4_5_SPSR_SVC,
+};
 
-       "r13_abt", "lr_abt",
+static const uint8_t arm_abt_indices[3] = {
+       27, 28, ARMV4_5_SPSR_ABT,
+};
 
-       "r13_und", "lr_und",
+static const uint8_t arm_und_indices[3] = {
+       29, 30, ARMV4_5_SPSR_UND,
+};
 
-       "cpsr", "spsr_fiq", "spsr_irq", "spsr_svc", "spsr_abt", "spsr_und"
+static const uint8_t arm_mon_indices[3] = {
+       37, 38, ARM_SPSR_MON,
 };
 
-static const char *armv4_5_mode_strings_list[] =
-{
-       "Illegal mode value", "User", "FIQ", "IRQ", "Supervisor", "Abort", "Undefined", "System"
+static const struct {
+       const char *name;
+       unsigned short psr;
+       /* For user and system modes, these list indices for all registers.
+        * otherwise they're just indices for the shadow registers and SPSR.
+        */
+       unsigned short n_indices;
+       const uint8_t *indices;
+} arm_mode_data[] = {
+       /* Seven modes are standard from ARM7 on. "System" and "User" share
+        * the same registers; other modes shadow from 3 to 8 registers.
+        */
+       {
+               .name = "User",
+               .psr = ARMV4_5_MODE_USR,
+               .n_indices = ARRAY_SIZE(arm_usr_indices),
+               .indices = arm_usr_indices,
+       },
+       {
+               .name = "FIQ",
+               .psr = ARMV4_5_MODE_FIQ,
+               .n_indices = ARRAY_SIZE(arm_fiq_indices),
+               .indices = arm_fiq_indices,
+       },
+       {
+               .name = "Supervisor",
+               .psr = ARMV4_5_MODE_SVC,
+               .n_indices = ARRAY_SIZE(arm_svc_indices),
+               .indices = arm_svc_indices,
+       },
+       {
+               .name = "Abort",
+               .psr = ARMV4_5_MODE_ABT,
+               .n_indices = ARRAY_SIZE(arm_abt_indices),
+               .indices = arm_abt_indices,
+       },
+       {
+               .name = "IRQ",
+               .psr = ARMV4_5_MODE_IRQ,
+               .n_indices = ARRAY_SIZE(arm_irq_indices),
+               .indices = arm_irq_indices,
+       },
+       {
+               .name = "Undefined instruction",
+               .psr = ARMV4_5_MODE_UND,
+               .n_indices = ARRAY_SIZE(arm_und_indices),
+               .indices = arm_und_indices,
+       },
+       {
+               .name = "System",
+               .psr = ARMV4_5_MODE_SYS,
+               .n_indices = ARRAY_SIZE(arm_usr_indices),
+               .indices = arm_usr_indices,
+       },
+       /* TrustZone "Security Extensions" add a secure monitor mode.
+        * This is distinct from a "debug monitor" which can support
+        * non-halting debug, in conjunction with some debuggers.
+        */
+       {
+               .name = "Secure Monitor",
+               .psr = ARM_MODE_MON,
+               .n_indices = ARRAY_SIZE(arm_mon_indices),
+               .indices = arm_mon_indices,
+       },
 };
 
-/* Hack! Yuk! allow -1 index, which simplifies codepaths elsewhere in the code */
-const char **armv4_5_mode_strings = armv4_5_mode_strings_list + 1;
+/** Map PSR mode bits to the name of an ARM processor operating mode. */
+const char *arm_mode_name(unsigned psr_mode)
+{
+       for (unsigned i = 0; i < ARRAY_SIZE(arm_mode_data); i++) {
+               if (arm_mode_data[i].psr == psr_mode)
+                       return arm_mode_data[i].name;
+       }
+       LOG_ERROR("unrecognized psr mode: %#02x", psr_mode);
+       return "UNRECOGNIZED";
+}
+
+/** Return true iff the parameter denotes a valid ARM processor mode. */
+bool is_arm_mode(unsigned psr_mode)
+{
+       for (unsigned i = 0; i < ARRAY_SIZE(arm_mode_data); i++) {
+               if (arm_mode_data[i].psr == psr_mode)
+                       return true;
+       }
+       return false;
+}
 
-/** Map PSR mode bits to linear number */
+/** Map PSR mode bits to linear number indexing armv4_5_core_reg_map */
 int armv4_5_mode_to_number(enum armv4_5_mode mode)
 {
        switch (mode) {
@@ -81,13 +182,15 @@ int armv4_5_mode_to_number(enum armv4_5_mode mode)
                return 5;
        case ARMV4_5_MODE_SYS:
                return 6;
+       case ARM_MODE_MON:
+               return 7;
        default:
                LOG_ERROR("invalid mode value encountered %d", mode);
                return -1;
        }
 }
 
-/** Map linear number to PSR mode bits. */
+/** Map linear number indexing armv4_5_core_reg_map to PSR mode bits. */
 enum armv4_5_mode armv4_5_number_to_mode(int number)
 {
        switch (number) {
@@ -105,6 +208,8 @@ enum armv4_5_mode armv4_5_number_to_mode(int number)
                return ARMV4_5_MODE_UND;
        case 6:
                return ARMV4_5_MODE_SYS;
+       case 7:
+               return ARM_MODE_MON;
        default:
                LOG_ERROR("mode index out of bounds %d", number);
                return ARMV4_5_MODE_ANY;
@@ -113,63 +218,105 @@ enum armv4_5_mode armv4_5_number_to_mode(int number)
 
 char* armv4_5_state_strings[] =
 {
-       "ARM", "Thumb", "Jazelle"
+       "ARM", "Thumb", "Jazelle", "ThumbEE",
 };
 
-struct armv4_5_core_reg armv4_5_core_reg_list_arch_info[] =
-{
-       {0, ARMV4_5_MODE_ANY, NULL, NULL},
-       {1, ARMV4_5_MODE_ANY, NULL, NULL},
-       {2, ARMV4_5_MODE_ANY, NULL, NULL},
-       {3, ARMV4_5_MODE_ANY, NULL, NULL},
-       {4, ARMV4_5_MODE_ANY, NULL, NULL},
-       {5, ARMV4_5_MODE_ANY, NULL, NULL},
-       {6, ARMV4_5_MODE_ANY, NULL, NULL},
-       {7, ARMV4_5_MODE_ANY, NULL, NULL},
-       {8, ARMV4_5_MODE_ANY, NULL, NULL},
-       {9, ARMV4_5_MODE_ANY, NULL, NULL},
-       {10, ARMV4_5_MODE_ANY, NULL, NULL},
-       {11, ARMV4_5_MODE_ANY, NULL, NULL},
-       {12, ARMV4_5_MODE_ANY, NULL, NULL},
-       {13, ARMV4_5_MODE_USR, NULL, NULL},
-       {14, ARMV4_5_MODE_USR, NULL, NULL},
-       {15, ARMV4_5_MODE_ANY, NULL, NULL},
-
-       {8, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {9, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {10, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {11, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {12, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {13, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {14, ARMV4_5_MODE_FIQ, NULL, NULL},
-
-       {13, ARMV4_5_MODE_IRQ, NULL, NULL},
-       {14, ARMV4_5_MODE_IRQ, NULL, NULL},
-
-       {13, ARMV4_5_MODE_SVC, NULL, NULL},
-       {14, ARMV4_5_MODE_SVC, NULL, NULL},
-
-       {13, ARMV4_5_MODE_ABT, NULL, NULL},
-       {14, ARMV4_5_MODE_ABT, NULL, NULL},
-
-       {13, ARMV4_5_MODE_UND, NULL, NULL},
-       {14, ARMV4_5_MODE_UND, NULL, NULL},
-
-       {16, ARMV4_5_MODE_ANY, NULL, NULL},
-       {16, ARMV4_5_MODE_FIQ, NULL, NULL},
-       {16, ARMV4_5_MODE_IRQ, NULL, NULL},
-       {16, ARMV4_5_MODE_SVC, NULL, NULL},
-       {16, ARMV4_5_MODE_ABT, NULL, NULL},
-       {16, ARMV4_5_MODE_UND, NULL, NULL}
+/* Templates for ARM core registers.
+ *
+ * NOTE:  offsets in this table are coupled to the arm_mode_data
+ * table above, the armv4_5_core_reg_map array below, and also to
+ * the ARMV4_5_CPSR symbol (which should vanish after ARM11 updates).
+ */
+static const struct {
+       /* The name is used for e.g. the "regs" command. */
+       const char *name;
+
+       /* The {cookie, mode} tuple uniquely identifies one register.
+        * In a given mode, cookies 0..15 map to registers R0..R15,
+        * with R13..R15 usually called SP, LR, PC.
+        *
+        * MODE_ANY is used as *input* to the mapping, and indicates
+        * various special cases (sigh) and errors.
+        *
+        * Cookie 16 is (currently) confusing, since it indicates
+        * CPSR -or- SPSR depending on whether 'mode' is MODE_ANY.
+        * (Exception modes have both CPSR and SPSR registers ...)
+        */
+       unsigned cookie;
+       enum armv4_5_mode mode;
+} arm_core_regs[] = {
+       /* IMPORTANT:  we guarantee that the first eight cached registers
+        * correspond to r0..r7, and the fifteenth to PC, so that callers
+        * don't need to map them.
+        */
+       { .name = "r0", .cookie = 0, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r1", .cookie = 1, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r2", .cookie = 2, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r3", .cookie = 3, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r4", .cookie = 4, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r5", .cookie = 5, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r6", .cookie = 6, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r7", .cookie = 7, .mode = ARMV4_5_MODE_ANY, },
+
+       /* NOTE: regs 8..12 might be shadowed by FIQ ... flagging
+        * them as MODE_ANY creates special cases.  (ANY means
+        * "not mapped" elsewhere; here it's "everything but FIQ".)
+        */
+       { .name = "r8", .cookie = 8, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r9", .cookie = 9, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r10", .cookie = 10, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r11", .cookie = 11, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "r12", .cookie = 12, .mode = ARMV4_5_MODE_ANY, },
+
+       /* NOTE all MODE_USR registers are equivalent to MODE_SYS ones */
+       { .name = "sp_usr", .cookie = 13, .mode = ARMV4_5_MODE_USR, },
+       { .name = "lr_usr", .cookie = 14, .mode = ARMV4_5_MODE_USR, },
+
+       /* guaranteed to be at index 15 */
+       { .name = "pc", .cookie = 15, .mode = ARMV4_5_MODE_ANY, },
+
+       { .name = "r8_fiq", .cookie = 8, .mode = ARMV4_5_MODE_FIQ, },
+       { .name = "r9_fiq", .cookie = 9, .mode = ARMV4_5_MODE_FIQ, },
+       { .name = "r10_fiq", .cookie = 10, .mode = ARMV4_5_MODE_FIQ, },
+       { .name = "r11_fiq", .cookie = 11, .mode = ARMV4_5_MODE_FIQ, },
+       { .name = "r12_fiq", .cookie = 12, .mode = ARMV4_5_MODE_FIQ, },
+
+       { .name = "sp_fiq", .cookie = 13, .mode = ARMV4_5_MODE_FIQ, },
+       { .name = "lr_fiq", .cookie = 14, .mode = ARMV4_5_MODE_FIQ, },
+
+       { .name = "sp_irq", .cookie = 13, .mode = ARMV4_5_MODE_IRQ, },
+       { .name = "lr_irq", .cookie = 14, .mode = ARMV4_5_MODE_IRQ, },
+
+       { .name = "sp_svc", .cookie = 13, .mode = ARMV4_5_MODE_SVC, },
+       { .name = "lr_svc", .cookie = 14, .mode = ARMV4_5_MODE_SVC, },
+
+       { .name = "sp_abt", .cookie = 13, .mode = ARMV4_5_MODE_ABT, },
+       { .name = "lr_abt", .cookie = 14, .mode = ARMV4_5_MODE_ABT, },
+
+       { .name = "sp_und", .cookie = 13, .mode = ARMV4_5_MODE_UND, },
+       { .name = "lr_und", .cookie = 14, .mode = ARMV4_5_MODE_UND, },
+
+       { .name = "cpsr", .cookie = 16, .mode = ARMV4_5_MODE_ANY, },
+       { .name = "spsr_fiq", .cookie = 16, .mode = ARMV4_5_MODE_FIQ, },
+       { .name = "spsr_irq", .cookie = 16, .mode = ARMV4_5_MODE_IRQ, },
+       { .name = "spsr_svc", .cookie = 16, .mode = ARMV4_5_MODE_SVC, },
+       { .name = "spsr_abt", .cookie = 16, .mode = ARMV4_5_MODE_ABT, },
+       { .name = "spsr_und", .cookie = 16, .mode = ARMV4_5_MODE_UND, },
+
+       { .name = "sp_mon", .cookie = 13, .mode = ARM_MODE_MON, },
+       { .name = "lr_mon", .cookie = 14, .mode = ARM_MODE_MON, },
+       { .name = "spsr_mon", .cookie = 16, .mode = ARM_MODE_MON, },
 };
 
-/* map core mode (USR, FIQ, ...) and register number to indizes into the register cache */
-int armv4_5_core_reg_map[7][17] =
+/* map core mode (USR, FIQ, ...) and register number to
+ * indices into the register cache
+ */
+const int armv4_5_core_reg_map[8][17] =
 {
        {       /* USR */
                0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 31
        },
-       {       /* FIQ */
+       {       /* FIQ (8 shadows of USR, vs normal 3) */
                0, 1, 2, 3, 4, 5, 6, 7, 16, 17, 18, 19, 20, 21, 22, 15, 32
        },
        {       /* IRQ */
@@ -184,39 +331,145 @@ int armv4_5_core_reg_map[7][17] =
        {       /* UND */
                0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 29, 30, 15, 36
        },
-       {       /* SYS */
+       {       /* SYS (same registers as USR) */
                0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 31
+       },
+       {       /* MON */
+               0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 37, 38, 15, 39,
        }
 };
 
-uint8_t armv4_5_gdb_dummy_fp_value[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+/**
+ * Configures host-side ARM records to reflect the specified CPSR.
+ * Later, code can use arm_reg_current() to map register numbers
+ * according to how they are exposed by this mode.
+ */
+void arm_set_cpsr(struct arm *arm, uint32_t cpsr)
+{
+       enum armv4_5_mode mode = cpsr & 0x1f;
+       int num;
+
+       /* NOTE:  this may be called very early, before the register
+        * cache is set up.  We can't defend against many errors, in
+        * particular against CPSRs that aren't valid *here* ...
+        */
+       if (arm->cpsr) {
+               buf_set_u32(arm->cpsr->value, 0, 32, cpsr);
+               arm->cpsr->valid = 1;
+               arm->cpsr->dirty = 0;
+       }
+
+       arm->core_mode = mode;
+
+       /* mode_to_number() warned; set up a somewhat-sane mapping */
+       num = armv4_5_mode_to_number(mode);
+       if (num < 0) {
+               mode = ARMV4_5_MODE_USR;
+               num = 0;
+       }
+
+       arm->map = &armv4_5_core_reg_map[num][0];
+       arm->spsr = (mode == ARMV4_5_MODE_USR || mode == ARMV4_5_MODE_SYS)
+                       ? NULL
+                       : arm->core_cache->reg_list + arm->map[16];
+
+       /* Older ARMs won't have the J bit */
+       enum armv4_5_state state;
+
+       if (cpsr & (1 << 5)) {  /* T */
+               if (cpsr & (1 << 24)) { /* J */
+                       LOG_WARNING("ThumbEE -- incomplete support");
+                       state = ARM_STATE_THUMB_EE;
+               } else
+                       state = ARMV4_5_STATE_THUMB;
+       } else {
+               if (cpsr & (1 << 24)) { /* J */
+                       LOG_ERROR("Jazelle state handling is BROKEN!");
+                       state = ARMV4_5_STATE_JAZELLE;
+               } else
+                       state = ARMV4_5_STATE_ARM;
+       }
+       arm->core_state = state;
+
+       LOG_DEBUG("set CPSR %#8.8x: %s mode, %s state", (unsigned) cpsr,
+                       arm_mode_name(mode),
+                       armv4_5_state_strings[arm->core_state]);
+}
 
-struct reg armv4_5_gdb_dummy_fp_reg =
+/**
+ * Returns handle to the register currently mapped to a given number.
+ * Someone must have called arm_set_cpsr() before.
+ *
+ * \param arm This core's state and registers are used.
+ * \param regnum From 0..15 corresponding to R0..R14 and PC.
+ *     Note that R0..R7 don't require mapping; you may access those
+ *     as the first eight entries in the register cache.  Likewise
+ *     R15 (PC) doesn't need mapping; you may also access it directly.
+ *     However, R8..R14, and SPSR (arm->spsr) *must* be mapped.
+ *     CPSR (arm->cpsr) is also not mapped.
+ */
+struct reg *arm_reg_current(struct arm *arm, unsigned regnum)
 {
-       .name = "GDB dummy floating-point register",
-       .value = armv4_5_gdb_dummy_fp_value,
-       .dirty = 0,
+       struct reg *r;
+
+       if (regnum > 16)
+               return NULL;
+
+       r = arm->core_cache->reg_list + arm->map[regnum];
+
+       /* e.g. invalid CPSR said "secure monitor" mode on a core
+        * that doesn't support it...
+        */
+       if (!r) {
+               LOG_ERROR("Invalid CPSR mode");
+               r = arm->core_cache->reg_list + regnum;
+       }
+
+       return r;
+}
+
+static const uint8_t arm_gdb_dummy_fp_value[12];
+
+/**
+ * Dummy FPA registers are required to support GDB on ARM.
+ * Register packets require eight obsolete FPA register values.
+ * Modern ARM cores use Vector Floating Point (VFP), if they
+ * have any floating point support.  VFP is not FPA-compatible.
+ */
+struct reg arm_gdb_dummy_fp_reg =
+{
+       .name = "GDB dummy FPA register",
+       .value = (uint8_t *) arm_gdb_dummy_fp_value,
        .valid = 1,
        .size = 96,
-       .arch_info = NULL,
 };
 
-uint8_t armv4_5_gdb_dummy_fps_value[] = {0, 0, 0, 0};
+static const uint8_t arm_gdb_dummy_fps_value[4];
 
-struct reg armv4_5_gdb_dummy_fps_reg =
+/**
+ * Dummy FPA status registers are required to support GDB on ARM.
+ * Register packets require an obsolete FPA status register.
+ */
+struct reg arm_gdb_dummy_fps_reg =
 {
-       .name = "GDB dummy floating-point status register",
-       .value = armv4_5_gdb_dummy_fps_value,
-       .dirty = 0,
+       .name = "GDB dummy FPA status register",
+       .value = (uint8_t *) arm_gdb_dummy_fps_value,
        .valid = 1,
        .size = 32,
-       .arch_info = NULL,
 };
 
-int armv4_5_get_core_reg(struct reg *reg)
+static void arm_gdb_dummy_init(void) __attribute__ ((constructor));
+
+static void arm_gdb_dummy_init(void)
+{
+       register_init_dummy(&arm_gdb_dummy_fp_reg);
+       register_init_dummy(&arm_gdb_dummy_fps_reg);
+}
+
+static int armv4_5_get_core_reg(struct reg *reg)
 {
        int retval;
-       struct armv4_5_core_reg *armv4_5 = reg->arch_info;
+       struct arm_reg *armv4_5 = reg->arch_info;
        struct target *target = armv4_5->target;
 
        if (target->state != TARGET_HALTED)
@@ -225,58 +478,52 @@ int armv4_5_get_core_reg(struct reg *reg)
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       /* retval = armv4_5->armv4_5_common->full_context(target); */
-       retval = armv4_5->armv4_5_common->read_core_reg(target, armv4_5->num, armv4_5->mode);
+       retval = armv4_5->armv4_5_common->read_core_reg(target, reg, armv4_5->num, armv4_5->mode);
+       if (retval == ERROR_OK) {
+               reg->valid = 1;
+               reg->dirty = 0;
+       }
 
        return retval;
 }
 
-int armv4_5_set_core_reg(struct reg *reg, uint8_t *buf)
+static int armv4_5_set_core_reg(struct reg *reg, uint8_t *buf)
 {
-       struct armv4_5_core_reg *armv4_5 = reg->arch_info;
+       struct arm_reg *armv4_5 = reg->arch_info;
        struct target *target = armv4_5->target;
-       struct armv4_5_common_s *armv4_5_target = target_to_armv4_5(target);
+       struct arm *armv4_5_target = target_to_armv4_5(target);
        uint32_t value = buf_get_u32(buf, 0, 32);
 
        if (target->state != TARGET_HALTED)
        {
+               LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       if (reg == &armv4_5_target->core_cache->reg_list[ARMV4_5_CPSR])
-       {
-               if (value & 0x20)
-               {
-                       /* T bit should be set */
-                       if (armv4_5_target->core_state == ARMV4_5_STATE_ARM)
-                       {
-                               /* change state to Thumb */
-                               LOG_DEBUG("changing to Thumb state");
-                               armv4_5_target->core_state = ARMV4_5_STATE_THUMB;
-                       }
-               }
-               else
-               {
-                       /* T bit should be cleared */
-                       if (armv4_5_target->core_state == ARMV4_5_STATE_THUMB)
-                       {
-                               /* change state to ARM */
-                               LOG_DEBUG("changing to ARM state");
-                               armv4_5_target->core_state = ARMV4_5_STATE_ARM;
-                       }
-               }
-
-               if (armv4_5_target->core_mode != (enum armv4_5_mode)(value & 0x1f))
-               {
-                       LOG_DEBUG("changing ARM core mode to '%s'", armv4_5_mode_strings[armv4_5_mode_to_number(value & 0x1f)]);
-                       armv4_5_target->core_mode = value & 0x1f;
-                       armv4_5_target->write_core_reg(target, 16, ARMV4_5_MODE_ANY, value);
+       /* Except for CPSR, the "reg" command exposes a writeback model
+        * for the register cache.
+        */
+       if (reg == armv4_5_target->cpsr) {
+               arm_set_cpsr(armv4_5_target, value);
+
+               /* Older cores need help to be in ARM mode during halt
+                * mode debug, so we clear the J and T bits if we flush.
+                * For newer cores (v6/v7a/v7r) we don't need that, but
+                * it won't hurt since CPSR is always flushed anyway.
+                */
+               if (armv4_5_target->core_mode !=
+                               (enum armv4_5_mode)(value & 0x1f)) {
+                       LOG_DEBUG("changing ARM core mode to '%s'",
+                                       arm_mode_name(value & 0x1f));
+                       value &= ~((1 << 24) | (1 << 5));
+                       armv4_5_target->write_core_reg(target, reg,
+                                       16, ARMV4_5_MODE_ANY, value);
                }
+       } else {
+               buf_set_u32(reg->value, 0, 32, value);
+               reg->valid = 1;
        }
-
-       buf_set_u32(reg->value, 0, 32, value);
        reg->dirty = 1;
-       reg->valid = 1;
 
        return ERROR_OK;
 }
@@ -286,56 +533,57 @@ static const struct reg_arch_type arm_reg_type = {
        .set = armv4_5_set_core_reg,
 };
 
-int armv4_5_invalidate_core_regs(struct target *target)
-{
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
-       int i;
-
-       for (i = 0; i < 37; i++)
-       {
-               armv4_5->core_cache->reg_list[i].valid = 0;
-               armv4_5->core_cache->reg_list[i].dirty = 0;
-       }
-
-       return ERROR_OK;
-}
-
 struct reg_cache* armv4_5_build_reg_cache(struct target *target, struct arm *armv4_5_common)
 {
-       int num_regs = 37;
+       int num_regs = ARRAY_SIZE(arm_core_regs);
        struct reg_cache *cache = malloc(sizeof(struct reg_cache));
-       struct reg *reg_list = malloc(sizeof(struct reg) * num_regs);
-       struct armv4_5_core_reg *arch_info = malloc(sizeof(struct armv4_5_core_reg) * num_regs);
+       struct reg *reg_list = calloc(num_regs, sizeof(struct reg));
+       struct arm_reg *arch_info = calloc(num_regs, sizeof(struct arm_reg));
        int i;
 
-       cache->name = "arm v4/5 registers";
+       if (!cache || !reg_list || !arch_info) {
+               free(cache);
+               free(reg_list);
+               free(arch_info);
+               return NULL;
+       }
+
+       cache->name = "ARM registers";
        cache->next = NULL;
        cache->reg_list = reg_list;
-       cache->num_regs = num_regs;
-
-       register_init_dummy(&armv4_5_gdb_dummy_fp_reg);
-       register_init_dummy(&armv4_5_gdb_dummy_fps_reg);
+       cache->num_regs = 0;
 
-       for (i = 0; i < 37; i++)
+       for (i = 0; i < num_regs; i++)
        {
-               arch_info[i] = armv4_5_core_reg_list_arch_info[i];
+               /* Skip registers this core doesn't expose */
+               if (arm_core_regs[i].mode == ARM_MODE_MON
+                               && armv4_5_common->core_type != ARM_MODE_MON)
+                       continue;
+
+               /* REVISIT handle Cortex-M, which only shadows R13/SP */
+
+               arch_info[i].num = arm_core_regs[i].cookie;
+               arch_info[i].mode = arm_core_regs[i].mode;
                arch_info[i].target = target;
                arch_info[i].armv4_5_common = armv4_5_common;
-               reg_list[i].name = armv4_5_core_reg_list[i];
+
+               reg_list[i].name = (char *) arm_core_regs[i].name;
                reg_list[i].size = 32;
-               reg_list[i].value = calloc(1, 4);
-               reg_list[i].dirty = 0;
-               reg_list[i].valid = 0;
+               reg_list[i].value = &arch_info[i].value;
                reg_list[i].type = &arm_reg_type;
                reg_list[i].arch_info = &arch_info[i];
+
+               cache->num_regs++;
        }
 
+       armv4_5_common->cpsr = reg_list + ARMV4_5_CPSR;
+       armv4_5_common->core_cache = cache;
        return cache;
 }
 
 int armv4_5_arch_state(struct target *target)
 {
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
+       struct arm *armv4_5 = target_to_armv4_5(target);
 
        if (armv4_5->common_magic != ARMV4_5_COMMON_MAGIC)
        {
@@ -346,95 +594,127 @@ int armv4_5_arch_state(struct target *target)
        LOG_USER("target halted in %s state due to %s, current mode: %s\ncpsr: 0x%8.8" PRIx32 " pc: 0x%8.8" PRIx32 "",
                         armv4_5_state_strings[armv4_5->core_state],
                         Jim_Nvp_value2name_simple(nvp_target_debug_reason, target->debug_reason)->name,
-                        armv4_5_mode_strings[armv4_5_mode_to_number(armv4_5->core_mode)],
-                        buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32),
+                        arm_mode_name(armv4_5->core_mode),
+                        buf_get_u32(armv4_5->cpsr->value, 0, 32),
                         buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32));
 
        return ERROR_OK;
 }
 
+#define ARMV4_5_CORE_REG_MODENUM(cache, mode, num) \
+               cache->reg_list[armv4_5_core_reg_map[mode][num]]
+
 COMMAND_HANDLER(handle_armv4_5_reg_command)
 {
-       char output[128];
-       int output_len;
-       int mode, num;
-       struct target *target = get_current_target(cmd_ctx);
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
+       struct target *target = get_current_target(CMD_CTX);
+       struct arm *armv4_5 = target_to_armv4_5(target);
+       unsigned num_regs;
+       struct reg *regs;
 
        if (!is_arm(armv4_5))
        {
-               command_print(cmd_ctx, "current target isn't an ARM");
+               command_print(CMD_CTX, "current target isn't an ARM");
                return ERROR_FAIL;
        }
 
        if (target->state != TARGET_HALTED)
        {
-               command_print(cmd_ctx, "error: target must be halted for register accesses");
-               return ERROR_OK;
+               command_print(CMD_CTX, "error: target must be halted for register accesses");
+               return ERROR_FAIL;
        }
 
-       if (armv4_5_mode_to_number(armv4_5->core_mode)==-1)
+       if (!is_arm_mode(armv4_5->core_mode))
                return ERROR_FAIL;
 
        if (!armv4_5->full_context) {
-               command_print(cmd_ctx, "error: target doesn't support %s",
+               command_print(CMD_CTX, "error: target doesn't support %s",
                                CMD_NAME);
                return ERROR_FAIL;
        }
 
-       for (num = 0; num <= 15; num++)
-       {
-               output_len = 0;
-               for (mode = 0; mode < 6; mode++)
-               {
-                       if (!ARMV4_5_CORE_REG_MODENUM(armv4_5->core_cache, mode, num).valid)
-                       {
-                               armv4_5->full_context(target);
-                       }
-                       output_len += snprintf(output + output_len,
-                                              128 - output_len,
+       num_regs = armv4_5->core_cache->num_regs;
+       regs = armv4_5->core_cache->reg_list;
+
+       for (unsigned mode = 0; mode < ARRAY_SIZE(arm_mode_data); mode++) {
+               const char *name;
+               char *sep = "\n";
+               char *shadow = "";
+
+               /* label this bank of registers (or shadows) */
+               switch (arm_mode_data[mode].psr) {
+               case ARMV4_5_MODE_SYS:
+                       continue;
+               case ARMV4_5_MODE_USR:
+                       name = "System and User";
+                       sep = "";
+                       break;
+               case ARM_MODE_MON:
+                       if (armv4_5->core_type != ARM_MODE_MON)
+                               continue;
+                       /* FALLTHROUGH */
+               default:
+                       name = arm_mode_data[mode].name;
+                       shadow = "shadow ";
+                       break;
+               }
+               command_print(CMD_CTX, "%s%s mode %sregisters",
+                               sep, name, shadow);
+
+               /* display N rows of up to 4 registers each */
+               for (unsigned i = 0; i < arm_mode_data[mode].n_indices;) {
+                       char output[80];
+                       int output_len = 0;
+
+                       for (unsigned j = 0; j < 4; j++, i++) {
+                               uint32_t value;
+                               struct reg *reg = regs;
+
+                               if (i >= arm_mode_data[mode].n_indices)
+                                       break;
+
+                               reg += arm_mode_data[mode].indices[i];
+
+                               /* REVISIT be smarter about faults... */
+                               if (!reg->valid)
+                                       armv4_5->full_context(target);
+
+                               value = buf_get_u32(reg->value, 0, 32);
+                               output_len += snprintf(output + output_len,
+                                               sizeof(output) - output_len,
                                               "%8s: %8.8" PRIx32 " ",
-                                              ARMV4_5_CORE_REG_MODENUM(armv4_5->core_cache, mode, num).name,
-                                              buf_get_u32(ARMV4_5_CORE_REG_MODENUM(armv4_5->core_cache, mode, num).value, 0, 32));
+                                              reg->name, value);
+                       }
+                       command_print(CMD_CTX, "%s", output);
                }
-               command_print(cmd_ctx, "%s", output);
        }
-       command_print(cmd_ctx,
-                     "    cpsr: %8.8" PRIx32 " spsr_fiq: %8.8" PRIx32 " spsr_irq: %8.8" PRIx32 " spsr_svc: %8.8" PRIx32 " spsr_abt: %8.8" PRIx32 " spsr_und: %8.8" PRIx32 "",
-                         buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32),
-                         buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_SPSR_FIQ].value, 0, 32),
-                         buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_SPSR_IRQ].value, 0, 32),
-                         buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_SPSR_SVC].value, 0, 32),
-                         buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_SPSR_ABT].value, 0, 32),
-                         buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_SPSR_UND].value, 0, 32));
 
        return ERROR_OK;
 }
 
 COMMAND_HANDLER(handle_armv4_5_core_state_command)
 {
-       struct target *target = get_current_target(cmd_ctx);
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
+       struct target *target = get_current_target(CMD_CTX);
+       struct arm *armv4_5 = target_to_armv4_5(target);
 
        if (!is_arm(armv4_5))
        {
-               command_print(cmd_ctx, "current target isn't an ARM");
+               command_print(CMD_CTX, "current target isn't an ARM");
                return ERROR_FAIL;
        }
 
-       if (argc > 0)
+       if (CMD_ARGC > 0)
        {
-               if (strcmp(args[0], "arm") == 0)
+               if (strcmp(CMD_ARGV[0], "arm") == 0)
                {
                        armv4_5->core_state = ARMV4_5_STATE_ARM;
                }
-               if (strcmp(args[0], "thumb") == 0)
+               if (strcmp(CMD_ARGV[0], "thumb") == 0)
                {
                        armv4_5->core_state = ARMV4_5_STATE_THUMB;
                }
        }
 
-       command_print(cmd_ctx, "core state: %s", armv4_5_state_strings[armv4_5->core_state]);
+       command_print(CMD_CTX, "core state: %s", armv4_5_state_strings[armv4_5->core_state]);
 
        return ERROR_OK;
 }
@@ -442,31 +722,31 @@ COMMAND_HANDLER(handle_armv4_5_core_state_command)
 COMMAND_HANDLER(handle_armv4_5_disassemble_command)
 {
        int retval = ERROR_OK;
-       struct target *target = get_current_target(cmd_ctx);
+       struct target *target = get_current_target(CMD_CTX);
        struct arm *arm = target ? target_to_arm(target) : NULL;
        uint32_t address;
        int count = 1;
        int thumb = 0;
 
        if (!is_arm(arm)) {
-               command_print(cmd_ctx, "current target isn't an ARM");
+               command_print(CMD_CTX, "current target isn't an ARM");
                return ERROR_FAIL;
        }
 
-       switch (argc) {
+       switch (CMD_ARGC) {
        case 3:
-               if (strcmp(args[2], "thumb") != 0)
+               if (strcmp(CMD_ARGV[2], "thumb") != 0)
                        goto usage;
                thumb = 1;
                /* FALL THROUGH */
        case 2:
-               COMMAND_PARSE_NUMBER(int, args[1], count);
+               COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], count);
                /* FALL THROUGH */
        case 1:
-               COMMAND_PARSE_NUMBER(u32, args[0], address);
+               COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], address);
                if (address & 0x01) {
                        if (!thumb) {
-                               command_print(cmd_ctx, "Disassemble as Thumb");
+                               command_print(CMD_CTX, "Disassemble as Thumb");
                                thumb = 1;
                        }
                        address &= ~1;
@@ -474,7 +754,7 @@ COMMAND_HANDLER(handle_armv4_5_disassemble_command)
                break;
        default:
 usage:
-               command_print(cmd_ctx,
+               command_print(CMD_CTX,
                        "usage: arm disassemble <address> [<count> ['thumb']]");
                count = 0;
                retval = ERROR_FAIL;
@@ -503,58 +783,210 @@ usage:
                        if (retval != ERROR_OK)
                                break;
                }
-               command_print(cmd_ctx, "%s", cur_instruction.text);
+               command_print(CMD_CTX, "%s", cur_instruction.text);
                address += cur_instruction.instruction_size;
        }
 
        return retval;
 }
 
-int armv4_5_register_commands(struct command_context *cmd_ctx)
+static int jim_mcrmrc(Jim_Interp *interp, int argc, Jim_Obj *const *argv)
 {
-       struct command *armv4_5_cmd;
-
-       armv4_5_cmd = register_command(cmd_ctx, NULL, "arm",
-                       NULL, COMMAND_ANY,
-                       "generic ARM commands");
-
-       register_command(cmd_ctx, armv4_5_cmd, "reg",
-                       handle_armv4_5_reg_command, COMMAND_EXEC,
-                       "display ARM core registers");
-       register_command(cmd_ctx, armv4_5_cmd, "core_state",
-                       handle_armv4_5_core_state_command, COMMAND_EXEC,
-                       "display/change ARM core state <arm | thumb>");
-       register_command(cmd_ctx, armv4_5_cmd, "disassemble",
-                       handle_armv4_5_disassemble_command, COMMAND_EXEC,
-                       "disassemble instructions "
-                               "<address> [<count> ['thumb']]");
+       struct command_context *context;
+       struct target *target;
+       struct arm *arm;
+       int retval;
 
-       return ERROR_OK;
+       context = Jim_GetAssocData(interp, "context");
+       if (context == NULL) {
+               LOG_ERROR("%s: no command context", __func__);
+               return JIM_ERR;
+       }
+       target = get_current_target(context);
+       if (target == NULL) {
+               LOG_ERROR("%s: no current target", __func__);
+               return JIM_ERR;
+       }
+       if (!target_was_examined(target)) {
+               LOG_ERROR("%s: not yet examined", target_name(target));
+               return JIM_ERR;
+       }
+       arm = target_to_arm(target);
+       if (!is_arm(arm)) {
+               LOG_ERROR("%s: not an ARM", target_name(target));
+               return JIM_ERR;
+       }
+
+       if ((argc < 6) || (argc > 7)) {
+               /* FIXME use the command name to verify # params... */
+               LOG_ERROR("%s: wrong number of arguments", __func__);
+               return JIM_ERR;
+       }
+
+       int cpnum;
+       uint32_t op1;
+       uint32_t op2;
+       uint32_t CRn;
+       uint32_t CRm;
+       uint32_t value;
+       long l;
+
+       /* NOTE:  parameter sequence matches ARM instruction set usage:
+        *      MCR     pNUM, op1, rX, CRn, CRm, op2    ; write CP from rX
+        *      MRC     pNUM, op1, rX, CRn, CRm, op2    ; read CP into rX
+        * The "rX" is necessarily omitted; it uses Tcl mechanisms.
+        */
+       retval = Jim_GetLong(interp, argv[1], &l);
+       if (retval != JIM_OK)
+               return retval;
+       if (l & ~0xf) {
+               LOG_ERROR("%s: %s %d out of range", __func__,
+                               "coprocessor", (int) l);
+               return JIM_ERR;
+       }
+       cpnum = l;
+
+       retval = Jim_GetLong(interp, argv[2], &l);
+       if (retval != JIM_OK)
+               return retval;
+       if (l & ~0x7) {
+               LOG_ERROR("%s: %s %d out of range", __func__,
+                               "op1", (int) l);
+               return JIM_ERR;
+       }
+       op1 = l;
+
+       retval = Jim_GetLong(interp, argv[3], &l);
+       if (retval != JIM_OK)
+               return retval;
+       if (l & ~0xf) {
+               LOG_ERROR("%s: %s %d out of range", __func__,
+                               "CRn", (int) l);
+               return JIM_ERR;
+       }
+       CRn = l;
+
+       retval = Jim_GetLong(interp, argv[4], &l);
+       if (retval != JIM_OK)
+               return retval;
+       if (l & ~0xf) {
+               LOG_ERROR("%s: %s %d out of range", __func__,
+                               "CRm", (int) l);
+               return JIM_ERR;
+       }
+       CRm = l;
+
+       retval = Jim_GetLong(interp, argv[5], &l);
+       if (retval != JIM_OK)
+               return retval;
+       if (l & ~0x7) {
+               LOG_ERROR("%s: %s %d out of range", __func__,
+                               "op2", (int) l);
+               return JIM_ERR;
+       }
+       op2 = l;
+
+       value = 0;
+
+       /* FIXME don't assume "mrc" vs "mcr" from the number of params;
+        * that could easily be a typo!  Check both...
+        *
+        * FIXME change the call syntax here ... simplest to just pass
+        * the MRC() or MCR() instruction to be executed.  That will also
+        * let us support the "mrc2" and "mcr2" opcodes (toggling one bit)
+        * if that's ever needed.
+        */
+       if (argc == 7) {
+               retval = Jim_GetLong(interp, argv[6], &l);
+               if (retval != JIM_OK) {
+                       return retval;
+               }
+               value = l;
+
+               /* NOTE: parameters reordered! */
+               // ARMV4_5_MCR(cpnum, op1, 0, CRn, CRm, op2)
+               retval = arm->mcr(target, cpnum, op1, op2, CRn, CRm, value);
+               if (retval != ERROR_OK)
+                       return JIM_ERR;
+       } else {
+               /* NOTE: parameters reordered! */
+               // ARMV4_5_MRC(cpnum, op1, 0, CRn, CRm, op2)
+               retval = arm->mrc(target, cpnum, op1, op2, CRn, CRm, &value);
+               if (retval != ERROR_OK)
+                       return JIM_ERR;
+
+               Jim_SetResult(interp, Jim_NewIntObj(interp, value));
+       }
+
+       return JIM_OK;
 }
 
+static const struct command_registration arm_exec_command_handlers[] = {
+       {
+               .name = "reg",
+               .handler = &handle_armv4_5_reg_command,
+               .mode = COMMAND_EXEC,
+               .help = "display ARM core registers",
+       },
+       {
+               .name = "core_state",
+               .handler = &handle_armv4_5_core_state_command,
+               .mode = COMMAND_EXEC,
+               .usage = "<arm | thumb>",
+               .help = "display/change ARM core state",
+       },
+       {
+               .name = "disassemble",
+               .handler = &handle_armv4_5_disassemble_command,
+               .mode = COMMAND_EXEC,
+               .usage = "<address> [<count> ['thumb']]",
+               .help = "disassemble instructions ",
+       },
+       {
+               .name = "mcr",
+               .mode = COMMAND_EXEC,
+               .jim_handler = &jim_mcrmrc,
+               .help = "write coprocessor register",
+               .usage = "cpnum op1 CRn op2 CRm value",
+       },
+       {
+               .name = "mrc",
+               .jim_handler = &jim_mcrmrc,
+               .help = "read coprocessor register",
+               .usage = "cpnum op1 CRn op2 CRm",
+       },
+
+       COMMAND_REGISTRATION_DONE
+};
+const struct command_registration arm_command_handlers[] = {
+       {
+               .name = "arm",
+               .mode = COMMAND_ANY,
+               .help = "ARM command group",
+               .chain = arm_exec_command_handlers,
+       },
+       COMMAND_REGISTRATION_DONE
+};
+
 int armv4_5_get_gdb_reg_list(struct target *target, struct reg **reg_list[], int *reg_list_size)
 {
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
+       struct arm *armv4_5 = target_to_armv4_5(target);
        int i;
 
-       if (armv4_5_mode_to_number(armv4_5->core_mode)==-1)
+       if (!is_arm_mode(armv4_5->core_mode))
                return ERROR_FAIL;
 
        *reg_list_size = 26;
        *reg_list = malloc(sizeof(struct reg*) * (*reg_list_size));
 
        for (i = 0; i < 16; i++)
-       {
-               (*reg_list)[i] = &ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, i);
-       }
+               (*reg_list)[i] = arm_reg_current(armv4_5, i);
 
        for (i = 16; i < 24; i++)
-       {
-               (*reg_list)[i] = &armv4_5_gdb_dummy_fp_reg;
-       }
+               (*reg_list)[i] = &arm_gdb_dummy_fp_reg;
 
-       (*reg_list)[24] = &armv4_5_gdb_dummy_fps_reg;
-       (*reg_list)[25] = &armv4_5->core_cache->reg_list[ARMV4_5_CPSR];
+       (*reg_list)[24] = &arm_gdb_dummy_fps_reg;
+       (*reg_list)[25] = armv4_5->cpsr;
 
        return ERROR_OK;
 }
@@ -563,7 +995,7 @@ int armv4_5_get_gdb_reg_list(struct target *target, struct reg **reg_list[], int
 static int armv4_5_run_algorithm_completion(struct target *target, uint32_t exit_point, int timeout_ms, void *arch_info)
 {
        int retval;
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
+       struct arm *armv4_5 = target_to_armv4_5(target);
 
        if ((retval = target_wait_state(target, TARGET_HALTED, timeout_ms)) != ERROR_OK)
        {
@@ -592,17 +1024,23 @@ static int armv4_5_run_algorithm_completion(struct target *target, uint32_t exit
        return ERROR_OK;
 }
 
-int armv4_5_run_algorithm_inner(struct target *target, int num_mem_params, struct mem_param *mem_params, int num_reg_params, struct reg_param *reg_params, uint32_t entry_point, uint32_t exit_point, int timeout_ms, void *arch_info, int (*run_it)(struct target *target, uint32_t exit_point, int timeout_ms, void *arch_info))
+int armv4_5_run_algorithm_inner(struct target *target,
+               int num_mem_params, struct mem_param *mem_params,
+               int num_reg_params, struct reg_param *reg_params,
+               uint32_t entry_point, uint32_t exit_point,
+               int timeout_ms, void *arch_info,
+               int (*run_it)(struct target *target, uint32_t exit_point,
+                               int timeout_ms, void *arch_info))
 {
-       struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target);
+       struct arm *armv4_5 = target_to_armv4_5(target);
        struct armv4_5_algorithm *armv4_5_algorithm_info = arch_info;
        enum armv4_5_state core_state = armv4_5->core_state;
-       enum armv4_5_mode core_mode = armv4_5->core_mode;
        uint32_t context[17];
        uint32_t cpsr;
        int exit_breakpoint_size = 0;
        int i;
        int retval = ERROR_OK;
+
        LOG_DEBUG("Running algorithm");
 
        if (armv4_5_algorithm_info->common_magic != ARMV4_5_COMMON_MAGIC)
@@ -617,7 +1055,7 @@ int armv4_5_run_algorithm_inner(struct target *target, int num_mem_params, struc
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       if (armv4_5_mode_to_number(armv4_5->core_mode)==-1)
+       if (!is_arm_mode(armv4_5->core_mode))
                return ERROR_FAIL;
 
        /* armv5 and later can terminate with BKPT instruction; less overhead */
@@ -627,13 +1065,21 @@ int armv4_5_run_algorithm_inner(struct target *target, int num_mem_params, struc
                return ERROR_FAIL;
        }
 
+       /* save r0..pc, cpsr-or-spsr, and then cpsr-for-sure;
+        * they'll be restored later.
+        */
        for (i = 0; i <= 16; i++)
        {
-               if (!ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5_algorithm_info->core_mode, i).valid)
-                       armv4_5->read_core_reg(target, i, armv4_5_algorithm_info->core_mode);
-               context[i] = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5_algorithm_info->core_mode, i).value, 0, 32);
+               struct reg *r;
+
+               r = &ARMV4_5_CORE_REG_MODE(armv4_5->core_cache,
+                               armv4_5_algorithm_info->core_mode, i);
+               if (!r->valid)
+                       armv4_5->read_core_reg(target, r, i,
+                                       armv4_5_algorithm_info->core_mode);
+               context[i] = buf_get_u32(r->value, 0, 32);
        }
-       cpsr = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32);
+       cpsr = buf_get_u32(armv4_5->cpsr->value, 0, 32);
 
        for (i = 0; i < num_mem_params; i++)
        {
@@ -677,10 +1123,12 @@ int armv4_5_run_algorithm_inner(struct target *target, int num_mem_params, struc
 
        if (armv4_5_algorithm_info->core_mode != ARMV4_5_MODE_ANY)
        {
-               LOG_DEBUG("setting core_mode: 0x%2.2x", armv4_5_algorithm_info->core_mode);
-               buf_set_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 5, armv4_5_algorithm_info->core_mode);
-               armv4_5->core_cache->reg_list[ARMV4_5_CPSR].dirty = 1;
-               armv4_5->core_cache->reg_list[ARMV4_5_CPSR].valid = 1;
+               LOG_DEBUG("setting core_mode: 0x%2.2x",
+                               armv4_5_algorithm_info->core_mode);
+               buf_set_u32(armv4_5->cpsr->value, 0, 5,
+                               armv4_5_algorithm_info->core_mode);
+               armv4_5->cpsr->dirty = 1;
+               armv4_5->cpsr->valid = 1;
        }
 
        /* terminate using a hardware or (ARMv5+) software breakpoint */
@@ -737,6 +1185,7 @@ int armv4_5_run_algorithm_inner(struct target *target, int num_mem_params, struc
                }
        }
 
+       /* restore everything we saved before (17 or 18 registers) */
        for (i = 0; i <= 16; i++)
        {
                uint32_t regvalue;
@@ -749,12 +1198,11 @@ int armv4_5_run_algorithm_inner(struct target *target, int num_mem_params, struc
                        ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5_algorithm_info->core_mode, i).dirty = 1;
                }
        }
-       buf_set_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32, cpsr);
-       armv4_5->core_cache->reg_list[ARMV4_5_CPSR].valid = 1;
-       armv4_5->core_cache->reg_list[ARMV4_5_CPSR].dirty = 1;
+
+       arm_set_cpsr(armv4_5, cpsr);
+       armv4_5->cpsr->dirty = 1;
 
        armv4_5->core_state = core_state;
-       armv4_5->core_mode = core_mode;
 
        return retval;
 }
@@ -934,13 +1382,58 @@ int arm_blank_check_memory(struct target *target,
        return ERROR_OK;
 }
 
+static int arm_full_context(struct target *target)
+{
+       struct arm *armv4_5 = target_to_armv4_5(target);
+       unsigned num_regs = armv4_5->core_cache->num_regs;
+       struct reg *reg = armv4_5->core_cache->reg_list;
+       int retval = ERROR_OK;
+
+       for (; num_regs && retval == ERROR_OK; num_regs--, reg++) {
+               if (reg->valid)
+                       continue;
+               retval = armv4_5_get_core_reg(reg);
+       }
+       return retval;
+}
+
+static int arm_default_mrc(struct target *target, int cpnum,
+               uint32_t op1, uint32_t op2,
+               uint32_t CRn, uint32_t CRm,
+               uint32_t *value)
+{
+       LOG_ERROR("%s doesn't implement MRC", target_type_name(target));
+       return ERROR_FAIL;
+}
+
+static int arm_default_mcr(struct target *target, int cpnum,
+               uint32_t op1, uint32_t op2,
+               uint32_t CRn, uint32_t CRm,
+               uint32_t value)
+{
+       LOG_ERROR("%s doesn't implement MCR", target_type_name(target));
+       return ERROR_FAIL;
+}
+
 int armv4_5_init_arch_info(struct target *target, struct arm *armv4_5)
 {
        target->arch_info = armv4_5;
+       armv4_5->target = target;
 
        armv4_5->common_magic = ARMV4_5_COMMON_MAGIC;
-       armv4_5->core_state = ARMV4_5_STATE_ARM;
-       armv4_5->core_mode = ARMV4_5_MODE_USR;
+       arm_set_cpsr(armv4_5, ARMV4_5_MODE_USR);
+
+       /* core_type may be overridden by subtype logic */
+       armv4_5->core_type = ARMV4_5_MODE_ANY;
+
+       /* default full_context() has no core-specific optimizations */
+       if (!armv4_5->full_context && armv4_5->read_core_reg)
+               armv4_5->full_context = arm_full_context;
+
+       if (!armv4_5->mrc)
+               armv4_5->mrc = arm_default_mrc;
+       if (!armv4_5->mcr)
+               armv4_5->mcr = arm_default_mcr;
 
        return ERROR_OK;
 }