1 /*-------------------------------------------------------------------------
3 pcode.h - post code generation
4 Written By - Scott Dattalo scott@dattalo.com
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 -------------------------------------------------------------------------*/
28 The post code generation is an assembler optimizer. The assembly code
29 produced by all of the previous steps is fully functional. This step
30 will attempt to analyze the flow of the assembly code and agressively
31 optimize it. The peep hole optimizer attempts to do the same thing.
32 As you may recall, the peep hole optimizer replaces blocks of assembly
33 with more optimal blocks (e.g. removing redundant register loads).
34 However, the peep hole optimizer has to be somewhat conservative since
35 an assembly program has implicit state information that's unavailable
36 when only a few instructions are examined.
37 Consider this example:
43 The movf seems redundant since we know that the W register already
44 contains the same value of t1. So a peep hole optimizer is tempted to
45 remove the "movf". However, this is dangerous since the movf affects
46 the flags in the status register (specifically the Z flag) and subsequent
47 code may depend upon this. Look at these two examples:
51 movf t1,w ; Can't remove this movf
57 movf t1,w ; This movf can be removed
58 xorwf t2,w ; since xorwf will over write Z
68 /***********************************************************************
71 * The DFPRINTF macro will call fprintf if PCODE_DEBUG is defined.
72 * The macro is used like:
74 * DPRINTF(("%s #%d\n","test", 1));
76 * The double parenthesis (()) are necessary
78 ***********************************************************************/
82 #define DFPRINTF(args) (fprintf args)
84 #define DFPRINTF(args) ;
88 /***********************************************************************
89 * PIC status bits - this will move into device dependent headers
90 ***********************************************************************/
94 #define PIC_RP0_BIT 5 /* Register Bank select bits RP1:0 : */
95 #define PIC_RP1_BIT 6 /* 00 - bank 0, 01 - bank 1, 10 - bank 2, 11 - bank 3 */
96 #define PIC_IRP_BIT 7 /* Indirect register page select */
98 /***********************************************************************
99 * PIC INTCON bits - this will move into device dependent headers
100 ***********************************************************************/
101 #define PIC_RBIF_BIT 0 /* Port B level has changed flag */
102 #define PIC_INTF_BIT 1 /* Port B bit 0 interrupt on edge flag */
103 #define PIC_T0IF_BIT 2 /* TMR0 has overflowed flag */
104 #define PIC_RBIE_BIT 3 /* Port B level has changed - Interrupt Enable */
105 #define PIC_INTE_BIT 4 /* Port B bit 0 interrupt on edge - Int Enable */
106 #define PIC_T0IE_BIT 5 /* TMR0 overflow Interrupt Enable */
107 #define PIC_PIE_BIT 6 /* Peripheral Interrupt Enable */
108 #define PIC_GIE_BIT 7 /* Global Interrupt Enable */
110 /***********************************************************************
112 ***********************************************************************/
118 /***********************************************************************
120 * PIC_OPTYPE - Operand types that are specific to the PIC architecture
122 * If a PIC assembly instruction has an operand then here is where we
123 * associate a type to it. For example,
127 * The movf has two operands: 'reg' and the W register. 'reg' is some
128 * arbitrary general purpose register, hence it has the type PO_GPR_REGISTER.
129 * The W register, which is the PIC's accumulator, has the type PO_W.
131 ***********************************************************************/
137 PO_NONE=0, // No operand e.g. NOP
138 PO_W, // The 'W' register
139 PO_STATUS, // The 'STATUS' register
140 PO_FSR, // The "file select register" (in 18c it's one of three)
141 PO_INDF, // The Indirect register
142 PO_INTCON, // Interrupt Control register
143 PO_GPR_REGISTER, // A general purpose register
144 PO_GPR_BIT, // A bit of a general purpose register
145 PO_GPR_TEMP, // A general purpose temporary register
146 PO_SFR_REGISTER, // A special function register (e.g. PORTA)
147 PO_PCL, // Program counter Low register
148 PO_PCLATH, // Program counter Latch high register
149 PO_LITERAL, // A constant
150 PO_IMMEDIATE, // (8051 legacy)
151 PO_DIR, // Direct memory (8051 legacy)
152 PO_CRY, // bit memory (8051 legacy)
153 PO_BIT, // bit operand.
154 PO_STR, // (8051 legacy)
156 PO_WILD // Wild card operand in peep optimizer
160 /***********************************************************************
164 * This is not a list of the PIC's opcodes per se, but instead
165 * an enumeration of all of the different types of pic opcodes.
167 ***********************************************************************/
171 POC_WILD=-1, /* Wild card - used in the pCode peep hole optimizer
172 * to represent ANY pic opcode */
224 /***********************************************************************
225 * PC_TYPE - pCode Types
226 ***********************************************************************/
230 PC_COMMENT=0, /* pCode is a comment */
231 PC_INLINE, /* user's inline code */
232 PC_OPCODE, /* PORT dependent opcode */
233 PC_LABEL, /* assembly label */
234 PC_FLOW, /* flow analysis */
235 PC_FUNCTION, /* Function start or end */
236 PC_WILD, /* wildcard - an opcode place holder used
237 * in the pCode peep hole optimizer */
238 PC_CSOURCE /* C-Source Line */
241 /************************************************/
242 /*************** Structures ********************/
243 /************************************************/
245 struct pCodeWildBlock;
247 /*************************************************
250 The first step in optimizing pCode is determining
251 the program flow. This information is stored in
252 single-linked lists in the for of 'from' and 'to'
253 objects with in a pcode. For example, most instructions
254 don't involve any branching. So their from branch
255 points to the pCode immediately preceding them and
256 their 'to' branch points to the pcode immediately
257 following them. A skip instruction is an example of
258 a pcode that has multiple (in this case two) elements
259 in the 'to' branch. A 'label' pcode is an where there
260 may be multiple 'from' branches.
261 *************************************************/
263 typedef struct pBranch
265 struct pCode *pc; // Next pCode in a branch
266 struct pBranch *next; /* If more than one branch
267 * the next one is here */
271 /*************************************************
274 pCode Operand structure.
275 For those assembly instructions that have arguments,
276 the pCode will have a pCodeOp in which the argument
277 can be stored. For example
281 'some_register' will be stored/referenced in a pCodeOp
283 *************************************************/
285 typedef struct pCodeOp
292 typedef struct pCodeOpBit
296 unsigned int inBitSpace: 1; /* True if in bit space, else
297 just a bit of a register */
300 typedef struct pCodeOpLit
306 typedef struct pCodeOpImmd
309 int offset; /* low,med, or high byte of immediat value */
310 int index; /* add this to the immediate value */
311 unsigned _const:1; /* is in code space */
315 typedef struct pCodeOpLabel
321 typedef struct pCodeOpReg
323 pCodeOp pcop; // Can be either GPR or SFR
324 int rIdx; // Index into the register table
326 int instance; // byte # of Multi-byte registers
330 typedef struct pCodeOpRegBit
332 pCodeOpReg pcor; // The Register containing this bit
333 int bit; // 0-7 bit number.
334 PIC_OPTYPE subtype; // The type of this register.
335 unsigned int inBitSpace: 1; /* True if in bit space, else
336 just a bit of a register */
340 typedef struct pCodeOpWild
344 struct pCodeWildBlock *pcwb;
346 int id; /* index into an array of char *'s that will match
347 * the wild card. The array is in *pcp. */
348 pCodeOp *subtype; /* Pointer to the Operand type into which this wild
349 * card will be expanded */
350 pCodeOp *matched; /* When a wild matches, we'll store a pointer to the
351 * opcode we matched */
356 /*************************************************
359 Here is the basic build block of a PIC instruction.
360 Each pic instruction will get allocated a pCode.
361 A linked list of pCodes makes a program.
363 **************************************************/
369 struct pCode *prev; // The pCode objects are linked together
370 struct pCode *next; // in doubly linked lists.
372 int seq; // sequence number
374 struct pBlock *pb; // The pBlock that contains this pCode.
376 /* "virtual functions"
377 * The pCode structure is like a base class
378 * in C++. The subsequent structures that "inherit"
379 * the pCode structure will initialize these function
380 * pointers to something useful */
381 // void (*analyze) (struct pCode *_this);
382 void (*destruct)(struct pCode *_this);
383 void (*print) (FILE *of,struct pCode *_this);
388 /*************************************************
390 **************************************************/
392 typedef struct pCodeComment
401 /*************************************************
403 **************************************************/
405 typedef struct pCodeCSource
417 /*************************************************
420 The Flow object is used as marker to separate
421 the assembly code into contiguous chunks. In other
422 words, everytime an instruction cause or potentially
423 causes a branch, a Flow object will be inserted into
424 the pCode chain to mark the beginning of the next
426 **************************************************/
428 typedef struct pCodeFlow
433 pCode *end; /* Last pCode in this flow. Note that
434 the first pCode is pc.next */
436 set **uses; /* map the pCode instruction inCond and outCond conditions
437 * in this array of set's. The reason we allocate an
438 * array of pointers instead of declaring each type of
439 * usage is because there are port dependent usage definitions */
440 int nuses; /* number of uses sets */
442 set *from; /* flow blocks that can send control to this flow block */
443 set *to; /* flow blocks to which this one can send control */
445 int inCond; /* Input conditions - stuff assumed defined at entry */
446 int outCond; /* Output conditions - stuff modified by flow block */
448 int firstBank; /* The first and last bank flags are the first and last */
449 int lastBank; /* register banks used within one flow object */
456 /*************************************************
459 The Flow Link object is used to record information
460 about how consecutive excutive Flow objects are related.
461 The pCodeFlow objects demarcate the pCodeInstructions
462 into contiguous chunks. The FlowLink records conflicts
463 in the discontinuities. For example, if one Flow object
464 references a register in bank 0 and the next Flow object
465 references a register in bank 1, then there is a discontinuity
466 in the banking registers.
469 typedef struct pCodeFlowLink
471 pCodeFlow *pcflow; /* pointer to linked pCodeFlow object */
473 int bank_conflict; /* records bank conflicts */
477 /*************************************************
480 Here we describe all the facets of a PIC instruction
481 (expansion for the 18cxxx is also provided).
483 **************************************************/
485 typedef struct pCodeInstruction
490 PIC_OPCODE op; // The opcode of the instruction.
492 char const * const mnemonic; // Pointer to mnemonic string
494 pBranch *from; // pCodes that execute before this one
495 pBranch *to; // pCodes that execute after
496 pBranch *label; // pCode instructions that have labels
498 pCodeOp *pcop; /* Operand, if this instruction has one */
499 pCodeFlow *pcflow; /* flow block to which this instruction belongs */
500 pCodeCSource *cline; /* C Source from which this instruction was derived */
502 unsigned int num_ops; /* Number of operands (0,1,2 for mid range pics) */
503 unsigned int isModReg: 1; /* If destination is W or F, then 1==F */
504 unsigned int isBitInst: 1; /* e.g. BCF */
505 unsigned int isBranch: 1; /* True if this is a branching instruction */
506 unsigned int isSkip: 1; /* True if this is a skip instruction */
508 PIC_OPCODE inverted_op; /* Opcode of instruction that's the opposite of this one */
509 unsigned int inCond; // Input conditions for this instruction
510 unsigned int outCond; // Output conditions for this instruction
515 /*************************************************
517 **************************************************/
519 typedef struct pCodeLabel
529 /*************************************************
531 **************************************************/
533 typedef struct pCodeFunction
539 char *fname; /* If NULL, then this is the end of
540 a function. Otherwise, it's the
541 start and the name is contained
544 pBranch *from; // pCodes that execute before this one
545 pBranch *to; // pCodes that execute after
546 pBranch *label; // pCode instructions that have labels
548 int ncalled; /* Number of times function is called */
553 /*************************************************
555 **************************************************/
557 typedef struct pCodeWild
560 pCodeInstruction pci;
562 int id; /* Index into the wild card array of a peepBlock
563 * - this wild card will get expanded into that pCode
564 * that is stored at this index */
566 /* Conditions on wild pcode instruction */
567 int mustBeBitSkipInst:1;
568 int mustNotBeBitSkipInst:1;
569 int invertBitSkipInst:1;
571 pCodeOp *operand; // Optional operand
572 pCodeOp *label; // Optional label
576 /*************************************************
579 Here are PIC program snippets. There's a strong
580 correlation between the eBBlocks and pBlocks.
581 SDCC subdivides a C program into managable chunks.
582 Each chunk becomes a eBBlock and ultimately in the
585 **************************************************/
587 typedef struct pBlock
589 memmap *cmemmap; /* The snippet is from this memmap */
590 char dbName; /* if cmemmap is NULL, then dbName will identify the block */
591 pCode *pcHead; /* A pointer to the first pCode in a link list of pCodes */
592 pCode *pcTail; /* A pointer to the last pCode in a link list of pCodes */
594 struct pBlock *next; /* The pBlocks will form a doubly linked list */
597 set *function_entries; /* dll of functions in this pblock */
602 unsigned visited:1; /* set true if traversed in call tree */
604 unsigned seq; /* sequence number of this pBlock */
608 /*************************************************
611 The collection of pBlock program snippets are
612 placed into a linked list that is implemented
613 in the pFile structure.
615 The pcode optimizer will parse the pFile.
617 **************************************************/
621 pBlock *pbHead; /* A pointer to the first pBlock */
622 pBlock *pbTail; /* A pointer to the last pBlock */
624 pBranch *functions; /* A SLL of functions in this pFile */
630 /*************************************************
633 The pCodeWildBlock object keeps track of the wild
634 variables, operands, and opcodes that exist in
636 **************************************************/
637 typedef struct pCodeWildBlock {
639 struct pCodePeep *pcp; // pointer back to ... I don't like this...
641 int nvars; // Number of wildcard registers in target.
642 char **vars; // array of pointers to them
644 int nops; // Number of wildcard operands in target.
645 pCodeOp **wildpCodeOps; // array of pointers to the pCodeOp's.
647 int nwildpCodes; // Number of wildcard pCodes in target/replace
648 pCode **wildpCodes; // array of pointers to the pCode's.
652 /*************************************************
655 The pCodePeep object mimics the peep hole optimizer
656 in the main SDCC src (e.g. SDCCpeeph.c). Essentially
657 there is a target pCode chain and a replacement
658 pCode chain. The target chain is compared to the
659 pCode that is generated by gen.c. If a match is
660 found then the pCode is replaced by the replacement
662 **************************************************/
663 typedef struct pCodePeep {
664 pCodeWildBlock target; // code we'd like to optimize
665 pCodeWildBlock replace; // and this is what we'll optimize it with.
668 //pBlock replace; // and this is what we'll optimize it with.
672 /* (Note: a wildcard register is a place holder. Any register
673 * can be replaced by the wildcard when the pcode is being
674 * compared to the target. */
676 /* Post Conditions. A post condition is a condition that
677 * must be either true or false before the peep rule is
678 * accepted. For example, a certain rule may be accepted
679 * if and only if the Z-bit is not used as an input to
680 * the subsequent instructions in a pCode chain.
682 unsigned int postFalseCond;
683 unsigned int postTrueCond;
687 /*************************************************
689 pCode peep command definitions
691 Here are some special commands that control the
692 way the peep hole optimizer behaves
694 **************************************************/
696 enum peepCommandTypes{
703 /*************************************************
704 peepCommand structure stores the peep commands.
706 **************************************************/
708 typedef struct peepCommand {
714 /*************************************************
717 **************************************************/
718 #define PCODE(x) ((pCode *)(x))
719 #define PCI(x) ((pCodeInstruction *)(x))
720 #define PCL(x) ((pCodeLabel *)(x))
721 #define PCF(x) ((pCodeFunction *)(x))
722 #define PCFL(x) ((pCodeFlow *)(x))
723 #define PCW(x) ((pCodeWild *)(x))
724 #define PCCS(x) ((pCodeCSource *)(x))
726 #define PCOP(x) ((pCodeOp *)(x))
727 //#define PCOB(x) ((pCodeOpBit *)(x))
728 #define PCOL(x) ((pCodeOpLit *)(x))
729 #define PCOI(x) ((pCodeOpImmd *)(x))
730 #define PCOLAB(x) ((pCodeOpLabel *)(x))
731 #define PCOR(x) ((pCodeOpReg *)(x))
732 #define PCORB(x) ((pCodeOpRegBit *)(x))
733 #define PCOW(x) ((pCodeOpWild *)(x))
735 #define PBR(x) ((pBranch *)(x))
737 #define PCWB(x) ((pCodeWildBlock *)(x))
739 /*-----------------------------------------------------------------*
741 *-----------------------------------------------------------------*/
743 pCode *newpCode (PIC_OPCODE op, pCodeOp *pcop); // Create a new pCode given an operand
744 pCode *newpCodeCharP(char *cP); // Create a new pCode given a char *
745 pCode *newpCodeInlineP(char *cP); // Create a new pCode given a char *
746 pCode *newpCodeFunction(char *g, char *f); // Create a new function
747 pCode *newpCodeLabel(char *name,int key); // Create a new label given a key
748 pCode *newpCodeCSource(int ln, char *f, char *l); // Create a new symbol line
749 pBlock *newpCodeChain(memmap *cm,char c, pCode *pc); // Create a new pBlock
750 void printpBlock(FILE *of, pBlock *pb); // Write a pBlock to a file
751 void printpCode(FILE *of, pCode *pc); // Write a pCode to a file
752 void addpCode2pBlock(pBlock *pb, pCode *pc); // Add a pCode to a pBlock
753 void addpBlock(pBlock *pb); // Add a pBlock to a pFile
754 void copypCode(FILE *of, char dbName); // Write all pBlocks with dbName to *of
755 void movepBlock2Head(char dbName); // move pBlocks around
756 void AnalyzepCode(char dbName);
757 int OptimizepCode(char dbName);
758 void printCallTree(FILE *of);
759 void pCodePeepInit(void);
760 void pBlockConvert2ISR(pBlock *pb);
762 pCodeOp *newpCodeOpLabel(char *name, int key);
763 pCodeOp *newpCodeOpImmd(char *name, int offset, int index, int code_space);
764 pCodeOp *newpCodeOpLit(int lit);
765 pCodeOp *newpCodeOpBit(char *name, int bit,int inBitSpace);
766 pCodeOp *newpCodeOpRegFromStr(char *name);
767 pCodeOp *newpCodeOp(char *name, PIC_OPTYPE p);
768 pCodeOp *pCodeOpCopy(pCodeOp *pcop);
770 extern void pcode_test(void);
772 /*-----------------------------------------------------------------*
774 *-----------------------------------------------------------------*/
776 extern pCodeOpReg pc_status;
777 extern pCodeOpReg pc_intcon;
778 extern pCodeOpReg pc_indf;
779 extern pCodeOpReg pc_fsr;
780 extern pCodeOpReg pc_pcl;
781 extern pCodeOpReg pc_pclath;
782 extern pCodeOpReg pc_kzero;
783 extern pCodeOpReg pc_wsave; /* wsave and ssave are used to save W and the Status */
784 extern pCodeOpReg pc_ssave; /* registers during an interrupt */
787 #endif // __PCODE_H__
projects / fw / sdcc / blob