1 /*-------------------------------------------------------------------------
3 pcode.h - post code generation
4 Written By - Scott Dattalo scott@dattalo.com
5 Ported to PIC16 By - Martin Dubuc m.dubuc@rogers.com
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 -------------------------------------------------------------------------*/
29 The post code generation is an assembler optimizer. The assembly code
30 produced by all of the previous steps is fully functional. This step
31 will attempt to analyze the flow of the assembly code and agressively
32 optimize it. The peep hole optimizer attempts to do the same thing.
33 As you may recall, the peep hole optimizer replaces blocks of assembly
34 with more optimal blocks (e.g. removing redundant register loads).
35 However, the peep hole optimizer has to be somewhat conservative since
36 an assembly program has implicit state information that's unavailable
37 when only a few instructions are examined.
38 Consider this example:
44 The movf seems redundant since we know that the W register already
45 contains the same value of t1. So a peep hole optimizer is tempted to
46 remove the "movf". However, this is dangerous since the movf affects
47 the flags in the status register (specifically the Z flag) and subsequent
48 code may depend upon this. Look at these two examples:
52 movf t1,w ; Can't remove this movf
58 movf t1,w ; This movf can be removed
59 xorwf t2,w ; since xorwf will over write Z
69 /***********************************************************************
72 * The DFPRINTF macro will call fprintf if PCODE_DEBUG is defined.
73 * The macro is used like:
75 * DPRINTF(("%s #%d\n","test", 1));
77 * The double parenthesis (()) are necessary
79 ***********************************************************************/
83 #define DFPRINTF(args) (fprintf args)
85 #define DFPRINTF(args) ;
89 /***********************************************************************
90 * PIC status bits - this will move into device dependent headers
91 ***********************************************************************/
97 #define PIC_IRP_BIT 7 /* Indirect register page select */
99 /***********************************************************************
100 * PIC INTCON bits - this will move into device dependent headers
101 ***********************************************************************/
102 #define PIC_RBIF_BIT 0 /* Port B level has changed flag */
103 #define PIC_INTF_BIT 1 /* Port B bit 0 interrupt on edge flag */
104 #define PIC_T0IF_BIT 2 /* TMR0 has overflowed flag */
105 #define PIC_RBIE_BIT 3 /* Port B level has changed - Interrupt Enable */
106 #define PIC_INTE_BIT 4 /* Port B bit 0 interrupt on edge - Int Enable */
107 #define PIC_T0IE_BIT 5 /* TMR0 overflow Interrupt Enable */
108 #define PIC_PIE_BIT 6 /* Peripheral Interrupt Enable */
109 #define PIC_GIE_BIT 7 /* Global Interrupt Enable */
111 /***********************************************************************
112 * PIC bank definitions
113 ***********************************************************************/
114 #define PIC_BANK_FIRST 0
115 #define PIC_BANK_LAST 0xf
118 /***********************************************************************
120 ***********************************************************************/
126 /***********************************************************************
128 * PIC_OPTYPE - Operand types that are specific to the PIC architecture
130 * If a PIC assembly instruction has an operand then here is where we
131 * associate a type to it. For example,
135 * The movf has two operands: 'reg' and the W register. 'reg' is some
136 * arbitrary general purpose register, hence it has the type PO_GPR_REGISTER.
137 * The W register, which is the PIC's accumulator, has the type PO_W.
139 ***********************************************************************/
145 PO_NONE=0, // No operand e.g. NOP
146 PO_W, // The working register (as a destination)
147 PO_WREG, // The working register (as a file register)
148 PO_STATUS, // The 'STATUS' register
149 PO_BSR, // The 'BSR' register
150 PO_FSR0, // The "file select register" (in PIC18 family it's one
152 PO_INDF0, // The Indirect register
153 PO_INTCON, // Interrupt Control register
154 PO_GPR_REGISTER, // A general purpose register
155 PO_GPR_BIT, // A bit of a general purpose register
156 PO_GPR_TEMP, // A general purpose temporary register
157 PO_SFR_REGISTER, // A special function register (e.g. PORTA)
158 PO_PCL, // Program counter Low register
159 PO_PCLATH, // Program counter Latch high register
160 PO_LITERAL, // A constant
161 PO_REL_ADDR, // A relative address
162 PO_IMMEDIATE, // (8051 legacy)
163 PO_DIR, // Direct memory (8051 legacy)
164 PO_CRY, // bit memory (8051 legacy)
165 PO_BIT, // bit operand.
166 PO_STR, // (8051 legacy)
168 PO_WILD // Wild card operand in peep optimizer
172 /***********************************************************************
176 * This is not a list of the PIC's opcodes per se, but instead
177 * an enumeration of all of the different types of pic opcodes.
179 ***********************************************************************/
183 POC_WILD=-1, /* Wild card - used in the pCode peep hole optimizer
184 * to represent ANY pic opcode */
267 // POC_TRIS , // To be removed
275 /***********************************************************************
276 * PC_TYPE - pCode Types
277 ***********************************************************************/
281 PC_COMMENT=0, /* pCode is a comment */
282 PC_INLINE, /* user's inline code */
283 PC_OPCODE, /* PORT dependent opcode */
284 PC_LABEL, /* assembly label */
285 PC_FLOW, /* flow analysis */
286 PC_FUNCTION, /* Function start or end */
287 PC_WILD, /* wildcard - an opcode place holder used
288 * in the pCode peep hole optimizer */
289 PC_CSOURCE, /* C-Source Line */
290 PC_ASMDIR, /* Assembler directive */
291 PC_BAD /* Mark the pCode object as being bad */
294 /************************************************/
295 /*************** Structures ********************/
296 /************************************************/
297 /* These are here as forward references - the
298 * full definition of these are below */
300 struct pCodeWildBlock;
301 struct pCodeRegLives;
303 /*************************************************
306 The first step in optimizing pCode is determining
307 the program flow. This information is stored in
308 single-linked lists in the for of 'from' and 'to'
309 objects with in a pcode. For example, most instructions
310 don't involve any branching. So their from branch
311 points to the pCode immediately preceding them and
312 their 'to' branch points to the pcode immediately
313 following them. A skip instruction is an example of
314 a pcode that has multiple (in this case two) elements
315 in the 'to' branch. A 'label' pcode is an where there
316 may be multiple 'from' branches.
317 *************************************************/
319 typedef struct pBranch
321 struct pCode *pc; // Next pCode in a branch
322 struct pBranch *next; /* If more than one branch
323 * the next one is here */
327 /*************************************************
330 pCode Operand structure.
331 For those assembly instructions that have arguments,
332 the pCode will have a pCodeOp in which the argument
333 can be stored. For example
337 'some_register' will be stored/referenced in a pCodeOp
339 *************************************************/
341 typedef struct pCodeOp
349 typedef struct pCodeOpBit
353 unsigned int inBitSpace: 1; /* True if in bit space, else
354 just a bit of a register */
357 typedef struct pCodeOpLit
363 typedef struct pCodeOpLit2
371 typedef struct pCodeOpImmd
374 int offset; /* low,med, or high byte of immediat value */
375 int index; /* add this to the immediate value */
376 unsigned _const:1; /* is in code space */
378 int rIdx; /* If this immd points to a register */
379 struct regs *r; /* then this is the reg. */
383 typedef struct pCodeOpLabel
389 typedef struct pCodeOpReg
391 pCodeOp pcop; // Can be either GPR or SFR
392 int rIdx; // Index into the register table
394 int instance; // byte # of Multi-byte registers
398 typedef struct pCodeOpReg2
400 pCodeOp pcop; // used by default to all references
403 int instance; // assume same instance for both operands
406 pCodeOp *pcop2; // second memory operand
409 typedef struct pCodeOpRegBit
411 pCodeOpReg pcor; // The Register containing this bit
412 int bit; // 0-7 bit number.
413 PIC_OPTYPE subtype; // The type of this register.
414 unsigned int inBitSpace: 1; /* True if in bit space, else
415 just a bit of a register */
419 typedef struct pCodeOpWild
423 struct pCodeWildBlock *pcwb;
425 int id; /* index into an array of char *'s that will match
426 * the wild card. The array is in *pcp. */
427 pCodeOp *subtype; /* Pointer to the Operand type into which this wild
428 * card will be expanded */
429 pCodeOp *matched; /* When a wild matches, we'll store a pointer to the
430 * opcode we matched */
435 /*************************************************
438 Here is the basic build block of a PIC instruction.
439 Each pic instruction will get allocated a pCode.
440 A linked list of pCodes makes a program.
442 **************************************************/
448 struct pCode *prev; // The pCode objects are linked together
449 struct pCode *next; // in doubly linked lists.
451 int seq; // sequence number
453 struct pBlock *pb; // The pBlock that contains this pCode.
455 /* "virtual functions"
456 * The pCode structure is like a base class
457 * in C++. The subsequent structures that "inherit"
458 * the pCode structure will initialize these function
459 * pointers to something useful */
460 // void (*analyze) (struct pCode *_this);
461 void (*destruct)(struct pCode *_this);
462 void (*print) (FILE *of,struct pCode *_this);
467 /*************************************************
469 **************************************************/
471 typedef struct pCodeComment
481 /*************************************************
483 **************************************************/
485 typedef struct pCodeCSource
497 /*************************************************
499 **************************************************/
501 typedef struct pCodeAsmDir
512 /*************************************************
515 The Flow object is used as marker to separate
516 the assembly code into contiguous chunks. In other
517 words, everytime an instruction cause or potentially
518 causes a branch, a Flow object will be inserted into
519 the pCode chain to mark the beginning of the next
522 **************************************************/
524 typedef struct pCodeFlow
529 pCode *end; /* Last pCode in this flow. Note that
530 the first pCode is pc.next */
532 /* set **uses; * map the pCode instruction inCond and outCond conditions
533 * in this array of set's. The reason we allocate an
534 * array of pointers instead of declaring each type of
535 * usage is because there are port dependent usage definitions */
536 //int nuses; /* number of uses sets */
538 set *from; /* flow blocks that can send control to this flow block */
539 set *to; /* flow blocks to which this one can send control */
540 struct pCodeFlow *ancestor; /* The most immediate "single" pCodeFlow object that
541 * executes prior to this one. In many cases, this
542 * will be just the previous */
544 int inCond; /* Input conditions - stuff assumed defined at entry */
545 int outCond; /* Output conditions - stuff modified by flow block */
547 int firstBank; /* The first and last bank flags are the first and last */
548 int lastBank; /* register banks used within one flow object */
553 set *registers;/* Registers used in this flow */
557 /*************************************************
560 The Flow Link object is used to record information
561 about how consecutive excutive Flow objects are related.
562 The pCodeFlow objects demarcate the pCodeInstructions
563 into contiguous chunks. The FlowLink records conflicts
564 in the discontinuities. For example, if one Flow object
565 references a register in bank 0 and the next Flow object
566 references a register in bank 1, then there is a discontinuity
567 in the banking registers.
570 typedef struct pCodeFlowLink
572 pCodeFlow *pcflow; /* pointer to linked pCodeFlow object */
574 int bank_conflict; /* records bank conflicts */
578 /*************************************************
581 Here we describe all the facets of a PIC instruction
582 (expansion for the 18cxxx is also provided).
584 **************************************************/
586 typedef struct pCodeInstruction
591 PIC_OPCODE op; // The opcode of the instruction.
593 char const * const mnemonic; // Pointer to mnemonic string
595 pBranch *from; // pCodes that execute before this one
596 pBranch *to; // pCodes that execute after
597 pBranch *label; // pCode instructions that have labels
599 pCodeOp *pcop; /* Operand, if this instruction has one */
600 pCodeFlow *pcflow; /* flow block to which this instruction belongs */
601 pCodeCSource *cline; /* C Source from which this instruction was derived */
603 unsigned int num_ops; /* Number of operands (0,1,2 for mid range pics) */
604 unsigned int isModReg: 1; /* If destination is W or F, then 1==F */
605 unsigned int isBitInst: 1; /* e.g. BCF */
606 unsigned int isBranch: 1; /* True if this is a branching instruction */
607 unsigned int isSkip: 1; /* True if this is a skip instruction */
608 unsigned int isLit: 1; /* True if this instruction has an literal operand */
609 unsigned int isAccess: 1; /* True if this instruction has an access RAM operand */
610 unsigned int isFastCall: 1; /* True if this instruction has a fast call/return mode select operand */
611 unsigned int is2MemOp: 1; /* True is second operand is a memory operand VR - support for MOVFF */
612 unsigned int is2LitOp: 1; /* True if instruction takes 2 literal operands VR - support for LFSR */
614 PIC_OPCODE inverted_op; /* Opcode of instruction that's the opposite of this one */
615 unsigned int inCond; // Input conditions for this instruction
616 unsigned int outCond; // Output conditions for this instruction
618 #define PCI_MAGIC 0x6e12
619 unsigned int pci_magic; // sanity check for pci initialization
623 /*************************************************
625 **************************************************/
627 typedef struct pCodeLabel
637 /*************************************************
639 **************************************************/
641 typedef struct pCodeFunction
647 char *fname; /* If NULL, then this is the end of
648 a function. Otherwise, it's the
649 start and the name is contained
652 pBranch *from; // pCodes that execute before this one
653 pBranch *to; // pCodes that execute after
654 pBranch *label; // pCode instructions that have labels
656 int ncalled; /* Number of times function is called */
661 /*************************************************
663 **************************************************/
665 typedef struct pCodeWild
668 pCodeInstruction pci;
670 int id; /* Index into the wild card array of a peepBlock
671 * - this wild card will get expanded into that pCode
672 * that is stored at this index */
674 /* Conditions on wild pcode instruction */
675 int mustBeBitSkipInst:1;
676 int mustNotBeBitSkipInst:1;
677 int invertBitSkipInst:1;
679 pCodeOp *operand; // Optional operand
680 pCodeOp *label; // Optional label
684 /*************************************************
687 Here are PIC program snippets. There's a strong
688 correlation between the eBBlocks and pBlocks.
689 SDCC subdivides a C program into managable chunks.
690 Each chunk becomes a eBBlock and ultimately in the
693 **************************************************/
695 typedef struct pBlock
697 memmap *cmemmap; /* The snippet is from this memmap */
698 char dbName; /* if cmemmap is NULL, then dbName will identify the block */
699 pCode *pcHead; /* A pointer to the first pCode in a link list of pCodes */
700 pCode *pcTail; /* A pointer to the last pCode in a link list of pCodes */
702 struct pBlock *next; /* The pBlocks will form a doubly linked list */
705 set *function_entries; /* dll of functions in this pblock */
711 unsigned visited:1; /* set true if traversed in call tree */
713 unsigned seq; /* sequence number of this pBlock */
717 /*************************************************
720 The collection of pBlock program snippets are
721 placed into a linked list that is implemented
722 in the pFile structure.
724 The pcode optimizer will parse the pFile.
726 **************************************************/
730 pBlock *pbHead; /* A pointer to the first pBlock */
731 pBlock *pbTail; /* A pointer to the last pBlock */
733 pBranch *functions; /* A SLL of functions in this pFile */
739 /*************************************************
742 The pCodeWildBlock object keeps track of the wild
743 variables, operands, and opcodes that exist in
745 **************************************************/
746 typedef struct pCodeWildBlock {
748 struct pCodePeep *pcp; // pointer back to ... I don't like this...
750 int nvars; // Number of wildcard registers in target.
751 char **vars; // array of pointers to them
753 int nops; // Number of wildcard operands in target.
754 pCodeOp **wildpCodeOps; // array of pointers to the pCodeOp's.
756 int nwildpCodes; // Number of wildcard pCodes in target/replace
757 pCode **wildpCodes; // array of pointers to the pCode's.
761 /*************************************************
764 The pCodePeep object mimics the peep hole optimizer
765 in the main SDCC src (e.g. SDCCpeeph.c). Essentially
766 there is a target pCode chain and a replacement
767 pCode chain. The target chain is compared to the
768 pCode that is generated by gen.c. If a match is
769 found then the pCode is replaced by the replacement
771 **************************************************/
772 typedef struct pCodePeep {
773 pCodeWildBlock target; // code we'd like to optimize
774 pCodeWildBlock replace; // and this is what we'll optimize it with.
777 //pBlock replace; // and this is what we'll optimize it with.
781 /* (Note: a wildcard register is a place holder. Any register
782 * can be replaced by the wildcard when the pcode is being
783 * compared to the target. */
785 /* Post Conditions. A post condition is a condition that
786 * must be either true or false before the peep rule is
787 * accepted. For example, a certain rule may be accepted
788 * if and only if the Z-bit is not used as an input to
789 * the subsequent instructions in a pCode chain.
791 unsigned int postFalseCond;
792 unsigned int postTrueCond;
796 /*************************************************
798 pCode peep command definitions
800 Here are some special commands that control the
801 way the peep hole optimizer behaves
803 **************************************************/
805 enum peepCommandTypes{
812 /*************************************************
813 peepCommand structure stores the peep commands.
815 **************************************************/
817 typedef struct peepCommand {
822 /*************************************************
825 **************************************************/
826 #define PCODE(x) ((pCode *)(x))
827 #define PCI(x) ((pCodeInstruction *)(x))
828 #define PCL(x) ((pCodeLabel *)(x))
829 #define PCF(x) ((pCodeFunction *)(x))
830 #define PCFL(x) ((pCodeFlow *)(x))
831 #define PCFLINK(x)((pCodeFlowLink *)(x))
832 #define PCW(x) ((pCodeWild *)(x))
833 #define PCCS(x) ((pCodeCSource *)(x))
834 #define PCAD(x) ((pCodeAsmDir *)(x))
836 #define PCOP(x) ((pCodeOp *)(x))
837 //#define PCOB(x) ((pCodeOpBit *)(x))
838 #define PCOL(x) ((pCodeOpLit *)(x))
839 #define PCOI(x) ((pCodeOpImmd *)(x))
840 #define PCOLAB(x) ((pCodeOpLabel *)(x))
841 #define PCOR(x) ((pCodeOpReg *)(x))
842 #define PCOR2(x) ((pCodeOpReg2 *)(x))
843 #define PCORB(x) ((pCodeOpRegBit *)(x))
844 #define PCOW(x) ((pCodeOpWild *)(x))
846 #define PBR(x) ((pBranch *)(x))
848 #define PCWB(x) ((pCodeWildBlock *)(x))
852 macros for checking pCode types
854 #define isPCI(x) ((PCODE(x)->type == PC_OPCODE))
855 #define isPCI_BRANCH(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isBranch)
856 #define isPCI_SKIP(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip)
857 #define isPCI_LIT(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isLit)
858 #define isPCI_BITSKIP(x)((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip && PCI(x)->isBitInst)
859 #define isPCFL(x) ((PCODE(x)->type == PC_FLOW))
860 #define isPCF(x) ((PCODE(x)->type == PC_FUNCTION))
861 #define isPCL(x) ((PCODE(x)->type == PC_LABEL))
862 #define isPCW(x) ((PCODE(x)->type == PC_WILD))
863 #define isPCCS(x) ((PCODE(x)->type == PC_CSOURCE))
864 #define isASMDIR(x) ((PCODE(x)->type == PC_ASMDIR))
866 #define isCALL(x) ((isPCI(x)) && (PCI(x)->op == POC_CALL))
867 #define isSTATUS_REG(r) ((r)->pc_type == PO_STATUS)
868 #define isBSR_REG(r) ((r)->pc_type == PO_BSR)
869 #define isACCESS_BANK(r) (r->accessBank)
873 #define isPCOLAB(x) ((PCOP(x)->type) == PO_LABEL)
875 /*-----------------------------------------------------------------*
877 *-----------------------------------------------------------------*/
879 pCode *pic16_newpCode (PIC_OPCODE op, pCodeOp *pcop); // Create a new pCode given an operand
880 pCode *pic16_newpCodeCharP(char *cP); // Create a new pCode given a char *
881 pCode *pic16_newpCodeInlineP(char *cP); // Create a new pCode given a char *
882 pCode *pic16_newpCodeFunction(char *g, char *f); // Create a new function
883 pCode *pic16_newpCodeLabel(char *name,int key); // Create a new label given a key
884 pCode *pic16_newpCodeCSource(int ln, char *f, char *l); // Create a new symbol line
885 pBlock *pic16_newpCodeChain(memmap *cm,char c, pCode *pc); // Create a new pBlock
886 void pic16_printpBlock(FILE *of, pBlock *pb); // Write a pBlock to a file
887 void pic16_addpCode2pBlock(pBlock *pb, pCode *pc); // Add a pCode to a pBlock
888 void pic16_addpBlock(pBlock *pb); // Add a pBlock to a pFile
889 void pic16_copypCode(FILE *of, char dbName); // Write all pBlocks with dbName to *of
890 void pic16_movepBlock2Head(char dbName); // move pBlocks around
891 void pic16_AnalyzepCode(char dbName);
892 void pic16_AssignRegBanks(void);
893 void pic16_printCallTree(FILE *of);
894 void pCodePeepInit(void);
895 void pic16_pBlockConvert2ISR(pBlock *pb);
896 void pic16_pBlockConvert2Absolute(pBlock *pb);
898 pCodeOp *pic16_newpCodeOpLabel(char *name, int key);
899 pCodeOp *pic16_newpCodeOpImmd(char *name, int offset, int index, int code_space);
900 pCodeOp *pic16_newpCodeOpLit(int lit);
901 pCodeOp *pic16_newpCodeOpLit2(int lit, pCodeOp *arg2);
902 pCodeOp *pic16_newpCodeOpBit(char *name, int bit,int inBitSpace);
903 pCodeOp *pic16_newpCodeOpRegFromStr(char *name);
904 pCodeOp *pic16_newpCodeOp(char *name, PIC_OPTYPE p);
905 pCodeOp *pic16_pCodeOpCopy(pCodeOp *pcop);
907 pCode * pic16_findNextInstruction(pCode *pci);
908 pCode * pic16_findNextpCode(pCode *pc, PC_TYPE pct);
909 int pic16_isPCinFlow(pCode *pc, pCode *pcflow);
910 struct regs * pic16_getRegFromInstruction(pCode *pc);
911 struct regs * pic16_getRegFromInstruction2(pCode *pc);
913 extern void pic16_pcode_test(void);
914 extern int pic16_debug_verbose;
915 /*-----------------------------------------------------------------*
917 *-----------------------------------------------------------------*/
919 extern pCodeOpReg pic16_pc_status;
920 extern pCodeOpReg pic16_pc_intcon;
921 extern pCodeOpReg pic16_pc_indf0;
922 extern pCodeOpReg pic16_pc_fsr0;
923 extern pCodeOpReg pic16_pc_pcl;
924 extern pCodeOpReg pic16_pc_pclath;
925 extern pCodeOpReg pic16_pc_wreg;
926 extern pCodeOpReg pic16_pc_fsr1l;
927 extern pCodeOpReg pic16_pc_fsr1h;
928 extern pCodeOpReg pic16_pc_fsr2l;
929 extern pCodeOpReg pic16_pc_fsr2h;
930 extern pCodeOpReg pic16_pc_postinc1;
931 extern pCodeOpReg pic16_pc_postdec1;
932 extern pCodeOpReg pic16_pc_preinc1;
933 extern pCodeOpReg pic16_pc_preinc2;
934 extern pCodeOpReg pic16_pc_plusw2;
936 extern pCodeOpReg pic16_pc_kzero;
937 extern pCodeOpReg pic16_pc_wsave; /* wsave and ssave are used to save W and the Status */
938 extern pCodeOpReg pic16_pc_ssave; /* registers during an interrupt */
941 #endif // __PCODE_H__