mips: optimize write code for speed

[fw/openocd] / src / target / arm_opcodes.h

diff --git a/src/target/arm_opcodes.h b/src/target/arm_opcodes.h
index b3b51433a8d55bbc311ebdcd43328a923250432c..12a9ca8d5ebebb9383c415c55c83c67d3ba73a2c 100644 (file)
--- a/src/target/arm_opcodes.h
+++ b/src/target/arm_opcodes.h
@@ -2,6 +2,9 @@
  * Copyright (C) 2005 by Dominic Rath
  * Dominic.Rath@gmx.de
  *
+ * Copyright (C) 2006 by Magnus Lundin
+ * lundin@mlu.mine.nu
+ *
  * Copyright (C) 2008 by Spencer Oliver
  * spen@spen-soft.co.uk
  *
@@ -26,6 +29,11 @@
 #ifndef __ARM_OPCODES_H
 #define __ARM_OPCODES_H
 
+/**
+ * @file
+ * Macros used to generate various ARM or Thumb opcodes.
+ */
+
 /* ARM mode instructions */
 
 /* Store multiple increment after
@@ -78,6 +86,12 @@
 #define ARMV4_5_MSR_IM(Im, Rotate, Field, R) \
        (0xe320f000 | (Im)  | ((Rotate) << 8) | ((Field) << 16) | ((R) << 22))
 
+/* Load Register Word Immediate Post-Index
+ * Rd: register to load
+ * Rn: base register
+ */
+#define ARMV4_5_LDRW_IP(Rd, Rn)        (0xe4900004 | ((Rd) << 12) | ((Rn) << 16))
+
 /* Load Register Halfword Immediate Post-Index
  * Rd: register to load
  * Rn: base register
@@ -90,6 +104,12 @@
  */
 #define ARMV4_5_LDRB_IP(Rd, Rn)        (0xe4d00001 | ((Rd) << 12) | ((Rn) << 16))
 
+/* Store register Word Immediate Post-Index
+ * Rd: register to store
+ * Rn: base register
+ */
+#define ARMV4_5_STRW_IP(Rd, Rn)        (0xe4800004 | ((Rd) << 12) | ((Rn) << 16))
+
 /* Store register Halfword Immediate Post-Index
  * Rd: register to store
  * Rn: base register
@@ -145,9 +165,13 @@
 
 /* Thumb mode instructions
  *
- * FIXME there must be some reason all these opcodes are 32-bits
- * not 16-bits ... this should get either an explanatory comment,
- * or be changed not to duplicate the opcode.
+ * NOTE: these 16-bit opcodes fill both halves of a word with the same
+ * value.  The reason for this is that when we need to execute Thumb
+ * opcodes on ARM7/ARM9 cores (to switch to ARM state on debug entry),
+ * we must shift 32 bits to the bus using scan chain 1 ... if we write
+ * both halves, we don't need to track which half matters.  On ARMv6 and
+ * ARMv7 we don't execute Thumb instructions in debug mode; the ITR
+ * register does not accept Thumb (or Thumb2) opcodes.
  */
 
 /* Store register (Thumb mode)