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 pCodeOpImmd
366 int offset; /* low,med, or high byte of immediat value */
367 int index; /* add this to the immediate value */
368 unsigned _const:1; /* is in code space */
370 int rIdx; /* If this immd points to a register */
371 struct regs *r; /* then this is the reg. */
375 typedef struct pCodeOpLabel
381 typedef struct pCodeOpReg
383 pCodeOp pcop; // Can be either GPR or SFR
384 int rIdx; // Index into the register table
386 int instance; // byte # of Multi-byte registers
390 typedef struct pCodeOpReg2
392 pCodeOp pcop; // used by default to all references
395 int instance; // assume same instance for both operands
398 pCodeOp *pcop2; // second memory operand
406 typedef struct pCodeOpRegBit
408 pCodeOpReg pcor; // The Register containing this bit
409 int bit; // 0-7 bit number.
410 PIC_OPTYPE subtype; // The type of this register.
411 unsigned int inBitSpace: 1; /* True if in bit space, else
412 just a bit of a register */
416 typedef struct pCodeOpWild
420 struct pCodeWildBlock *pcwb;
422 int id; /* index into an array of char *'s that will match
423 * the wild card. The array is in *pcp. */
424 pCodeOp *subtype; /* Pointer to the Operand type into which this wild
425 * card will be expanded */
426 pCodeOp *matched; /* When a wild matches, we'll store a pointer to the
427 * opcode we matched */
432 /*************************************************
435 Here is the basic build block of a PIC instruction.
436 Each pic instruction will get allocated a pCode.
437 A linked list of pCodes makes a program.
439 **************************************************/
445 struct pCode *prev; // The pCode objects are linked together
446 struct pCode *next; // in doubly linked lists.
448 int seq; // sequence number
450 struct pBlock *pb; // The pBlock that contains this pCode.
452 /* "virtual functions"
453 * The pCode structure is like a base class
454 * in C++. The subsequent structures that "inherit"
455 * the pCode structure will initialize these function
456 * pointers to something useful */
457 // void (*analyze) (struct pCode *_this);
458 void (*destruct)(struct pCode *_this);
459 void (*print) (FILE *of,struct pCode *_this);
464 /*************************************************
466 **************************************************/
468 typedef struct pCodeComment
478 /*************************************************
480 **************************************************/
482 typedef struct pCodeCSource
494 /*************************************************
496 **************************************************/
498 typedef struct pCodeAsmDir
507 /*************************************************
510 The Flow object is used as marker to separate
511 the assembly code into contiguous chunks. In other
512 words, everytime an instruction cause or potentially
513 causes a branch, a Flow object will be inserted into
514 the pCode chain to mark the beginning of the next
517 **************************************************/
519 typedef struct pCodeFlow
524 pCode *end; /* Last pCode in this flow. Note that
525 the first pCode is pc.next */
527 /* set **uses; * map the pCode instruction inCond and outCond conditions
528 * in this array of set's. The reason we allocate an
529 * array of pointers instead of declaring each type of
530 * usage is because there are port dependent usage definitions */
531 //int nuses; /* number of uses sets */
533 set *from; /* flow blocks that can send control to this flow block */
534 set *to; /* flow blocks to which this one can send control */
535 struct pCodeFlow *ancestor; /* The most immediate "single" pCodeFlow object that
536 * executes prior to this one. In many cases, this
537 * will be just the previous */
539 int inCond; /* Input conditions - stuff assumed defined at entry */
540 int outCond; /* Output conditions - stuff modified by flow block */
542 int firstBank; /* The first and last bank flags are the first and last */
543 int lastBank; /* register banks used within one flow object */
548 set *registers;/* Registers used in this flow */
552 /*************************************************
555 The Flow Link object is used to record information
556 about how consecutive excutive Flow objects are related.
557 The pCodeFlow objects demarcate the pCodeInstructions
558 into contiguous chunks. The FlowLink records conflicts
559 in the discontinuities. For example, if one Flow object
560 references a register in bank 0 and the next Flow object
561 references a register in bank 1, then there is a discontinuity
562 in the banking registers.
565 typedef struct pCodeFlowLink
567 pCodeFlow *pcflow; /* pointer to linked pCodeFlow object */
569 int bank_conflict; /* records bank conflicts */
573 /*************************************************
576 Here we describe all the facets of a PIC instruction
577 (expansion for the 18cxxx is also provided).
579 **************************************************/
581 typedef struct pCodeInstruction
586 PIC_OPCODE op; // The opcode of the instruction.
588 char const * const mnemonic; // Pointer to mnemonic string
590 pBranch *from; // pCodes that execute before this one
591 pBranch *to; // pCodes that execute after
592 pBranch *label; // pCode instructions that have labels
594 pCodeOp *pcop; /* Operand, if this instruction has one */
595 pCodeFlow *pcflow; /* flow block to which this instruction belongs */
596 pCodeCSource *cline; /* C Source from which this instruction was derived */
598 unsigned int num_ops; /* Number of operands (0,1,2 for mid range pics) */
599 unsigned int isModReg: 1; /* If destination is W or F, then 1==F */
600 unsigned int isBitInst: 1; /* e.g. BCF */
601 unsigned int isBranch: 1; /* True if this is a branching instruction */
602 unsigned int isSkip: 1; /* True if this is a skip instruction */
603 unsigned int isLit: 1; /* True if this instruction has an literal operand */
604 unsigned int isAccess: 1; /* True if this instruction has an access RAM operand */
605 unsigned int isFastCall: 1; /* True if this instruction has a fast call/return mode select operand */
606 unsigned int is2MemOp: 1; /* True is second operand is a memory operand VR - support for MOVFF */
608 PIC_OPCODE inverted_op; /* Opcode of instruction that's the opposite of this one */
609 unsigned int inCond; // Input conditions for this instruction
610 unsigned int outCond; // Output conditions for this instruction
615 /*************************************************
617 **************************************************/
619 typedef struct pCodeLabel
629 /*************************************************
631 **************************************************/
633 typedef struct pCodeFunction
639 char *fname; /* If NULL, then this is the end of
640 a function. Otherwise, it's the
641 start and the name is contained
644 pBranch *from; // pCodes that execute before this one
645 pBranch *to; // pCodes that execute after
646 pBranch *label; // pCode instructions that have labels
648 int ncalled; /* Number of times function is called */
653 /*************************************************
655 **************************************************/
657 typedef struct pCodeWild
660 pCodeInstruction pci;
662 int id; /* Index into the wild card array of a peepBlock
663 * - this wild card will get expanded into that pCode
664 * that is stored at this index */
666 /* Conditions on wild pcode instruction */
667 int mustBeBitSkipInst:1;
668 int mustNotBeBitSkipInst:1;
669 int invertBitSkipInst:1;
671 pCodeOp *operand; // Optional operand
672 pCodeOp *label; // Optional label
676 /*************************************************
679 Here are PIC program snippets. There's a strong
680 correlation between the eBBlocks and pBlocks.
681 SDCC subdivides a C program into managable chunks.
682 Each chunk becomes a eBBlock and ultimately in the
685 **************************************************/
687 typedef struct pBlock
689 memmap *cmemmap; /* The snippet is from this memmap */
690 char dbName; /* if cmemmap is NULL, then dbName will identify the block */
691 pCode *pcHead; /* A pointer to the first pCode in a link list of pCodes */
692 pCode *pcTail; /* A pointer to the last pCode in a link list of pCodes */
694 struct pBlock *next; /* The pBlocks will form a doubly linked list */
697 set *function_entries; /* dll of functions in this pblock */
703 unsigned visited:1; /* set true if traversed in call tree */
705 unsigned seq; /* sequence number of this pBlock */
709 /*************************************************
712 The collection of pBlock program snippets are
713 placed into a linked list that is implemented
714 in the pFile structure.
716 The pcode optimizer will parse the pFile.
718 **************************************************/
722 pBlock *pbHead; /* A pointer to the first pBlock */
723 pBlock *pbTail; /* A pointer to the last pBlock */
725 pBranch *functions; /* A SLL of functions in this pFile */
731 /*************************************************
734 The pCodeWildBlock object keeps track of the wild
735 variables, operands, and opcodes that exist in
737 **************************************************/
738 typedef struct pCodeWildBlock {
740 struct pCodePeep *pcp; // pointer back to ... I don't like this...
742 int nvars; // Number of wildcard registers in target.
743 char **vars; // array of pointers to them
745 int nops; // Number of wildcard operands in target.
746 pCodeOp **wildpCodeOps; // array of pointers to the pCodeOp's.
748 int nwildpCodes; // Number of wildcard pCodes in target/replace
749 pCode **wildpCodes; // array of pointers to the pCode's.
753 /*************************************************
756 The pCodePeep object mimics the peep hole optimizer
757 in the main SDCC src (e.g. SDCCpeeph.c). Essentially
758 there is a target pCode chain and a replacement
759 pCode chain. The target chain is compared to the
760 pCode that is generated by gen.c. If a match is
761 found then the pCode is replaced by the replacement
763 **************************************************/
764 typedef struct pCodePeep {
765 pCodeWildBlock target; // code we'd like to optimize
766 pCodeWildBlock replace; // and this is what we'll optimize it with.
769 //pBlock replace; // and this is what we'll optimize it with.
773 /* (Note: a wildcard register is a place holder. Any register
774 * can be replaced by the wildcard when the pcode is being
775 * compared to the target. */
777 /* Post Conditions. A post condition is a condition that
778 * must be either true or false before the peep rule is
779 * accepted. For example, a certain rule may be accepted
780 * if and only if the Z-bit is not used as an input to
781 * the subsequent instructions in a pCode chain.
783 unsigned int postFalseCond;
784 unsigned int postTrueCond;
788 /*************************************************
790 pCode peep command definitions
792 Here are some special commands that control the
793 way the peep hole optimizer behaves
795 **************************************************/
797 enum peepCommandTypes{
804 /*************************************************
805 peepCommand structure stores the peep commands.
807 **************************************************/
809 typedef struct peepCommand {
814 /*************************************************
817 **************************************************/
818 #define PCODE(x) ((pCode *)(x))
819 #define PCI(x) ((pCodeInstruction *)(x))
820 #define PCL(x) ((pCodeLabel *)(x))
821 #define PCF(x) ((pCodeFunction *)(x))
822 #define PCFL(x) ((pCodeFlow *)(x))
823 #define PCFLINK(x)((pCodeFlowLink *)(x))
824 #define PCW(x) ((pCodeWild *)(x))
825 #define PCCS(x) ((pCodeCSource *)(x))
826 #define PCAD(x) ((pCodeAsmDir *)(x))
828 #define PCOP(x) ((pCodeOp *)(x))
829 //#define PCOB(x) ((pCodeOpBit *)(x))
830 #define PCOL(x) ((pCodeOpLit *)(x))
831 #define PCOI(x) ((pCodeOpImmd *)(x))
832 #define PCOLAB(x) ((pCodeOpLabel *)(x))
833 #define PCOR(x) ((pCodeOpReg *)(x))
834 #define PCOR2(x) ((pCodeOpReg2 *)(x))
835 #define PCORB(x) ((pCodeOpRegBit *)(x))
836 #define PCOW(x) ((pCodeOpWild *)(x))
838 #define PBR(x) ((pBranch *)(x))
840 #define PCWB(x) ((pCodeWildBlock *)(x))
844 macros for checking pCode types
846 #define isPCI(x) ((PCODE(x)->type == PC_OPCODE))
847 #define isPCI_BRANCH(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isBranch)
848 #define isPCI_SKIP(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip)
849 #define isPCI_LIT(x) ((PCODE(x)->type == PC_OPCODE) && PCI(x)->isLit)
850 #define isPCI_BITSKIP(x)((PCODE(x)->type == PC_OPCODE) && PCI(x)->isSkip && PCI(x)->isBitInst)
851 #define isPCFL(x) ((PCODE(x)->type == PC_FLOW))
852 #define isPCF(x) ((PCODE(x)->type == PC_FUNCTION))
853 #define isPCL(x) ((PCODE(x)->type == PC_LABEL))
854 #define isPCW(x) ((PCODE(x)->type == PC_WILD))
855 #define isPCCS(x) ((PCODE(x)->type == PC_CSOURCE))
856 #define isASMDIR(x) ((PCODE(x)->type == PC_ASMDIR))
858 #define isCALL(x) ((isPCI(x)) && (PCI(x)->op == POC_CALL))
859 #define isSTATUS_REG(r) ((r)->pc_type == PO_STATUS)
860 #define isBSR_REG(r) ((r)->pc_type == PO_BSR)
862 #define isACCESS_LOW(r) ((pic16_finalMapping[REG_ADDR(r)].bank == \
863 PIC_BANK_FIRST) && (REG_ADDR(r) < 0x80))
864 #define isACCESS_HI(r) (pic16_finalMapping[REG_ADDR(r)].bank == PIC_BANK_LAST)
867 #define isACCESS_BANK(r)(isACCESS_LOW(r) || isACCESS_HI(r))
869 #define isACCESS_BANK(r) (pic16_finalMapping[(r)->rIdx].isSFR \
870 || (pic16_finalMapping[(r)->rIdx].reg && pic16_finalMapping[(r)->rIdx].reg->isFixed))
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_printCallTree(FILE *of);
893 void pCodePeepInit(void);
894 void pic16_pBlockConvert2ISR(pBlock *pb);
896 pCodeOp *pic16_newpCodeOpLabel(char *name, int key);
897 pCodeOp *pic16_newpCodeOpImmd(char *name, int offset, int index, int code_space);
898 pCodeOp *pic16_newpCodeOpLit(int lit);
899 pCodeOp *pic16_newpCodeOpBit(char *name, int bit,int inBitSpace);
900 pCodeOp *pic16_newpCodeOpRegFromStr(char *name);
901 pCodeOp *pic16_newpCodeOp(char *name, PIC_OPTYPE p);
902 pCodeOp *pic16_pCodeOpCopy(pCodeOp *pcop);
904 pCode * pic16_findNextInstruction(pCode *pci);
905 pCode * pic16_findNextpCode(pCode *pc, PC_TYPE pct);
906 int pic16_isPCinFlow(pCode *pc, pCode *pcflow);
907 struct regs * pic16_getRegFromInstruction(pCode *pc);
908 struct regs * pic16_getRegFromInstruction2(pCode *pc);
910 extern void pic16_pcode_test(void);
912 /*-----------------------------------------------------------------*
914 *-----------------------------------------------------------------*/
916 extern pCodeOpReg pic16_pc_status;
917 extern pCodeOpReg pic16_pc_intcon;
918 extern pCodeOpReg pic16_pc_indf0;
919 extern pCodeOpReg pic16_pc_fsr0;
920 extern pCodeOpReg pic16_pc_pcl;
921 extern pCodeOpReg pic16_pc_pclath;
922 extern pCodeOpReg pic16_pc_wreg;
923 extern pCodeOpReg pic16_pc_kzero;
924 extern pCodeOpReg pic16_pc_wsave; /* wsave and ssave are used to save W and the Status */
925 extern pCodeOpReg pic16_pc_ssave; /* registers during an interrupt */
928 #endif // __PCODE_H__