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_OPCODE, /* PORT dependent opcode */
232 PC_LABEL, /* assembly label */
233 PC_FLOW, /* flow analysis */
234 PC_FUNCTION, /* Function start or end */
235 PC_WILD /* wildcard - an opcode place holder used
236 * in the pCode peep hole optimizer */
239 /************************************************/
240 /*************** Structures ********************/
241 /************************************************/
243 struct pCodeWildBlock;
245 /*************************************************
248 The first step in optimizing pCode is determining
249 the program flow. This information is stored in
250 single-linked lists in the for of 'from' and 'to'
251 objects with in a pcode. For example, most instructions
252 don't involve any branching. So their from branch
253 points to the pCode immediately preceding them and
254 their 'to' branch points to the pcode immediately
255 following them. A skip instruction is an example of
256 a pcode that has multiple (in this case two) elements
257 in the 'to' branch. A 'label' pcode is an where there
258 may be multiple 'from' branches.
259 *************************************************/
261 typedef struct pBranch
263 struct pCode *pc; // Next pCode in a branch
264 struct pBranch *next; /* If more than one branch
265 * the next one is here */
269 /*************************************************
272 pCode Operand structure.
273 For those assembly instructions that have arguments,
274 the pCode will have a pCodeOp in which the argument
275 can be stored. For example
279 'some_register' will be stored/referenced in a pCodeOp
281 *************************************************/
283 typedef struct pCodeOp
290 typedef struct pCodeOpBit
294 unsigned int inBitSpace: 1; /* True if in bit space, else
295 just a bit of a register */
298 typedef struct pCodeOpLit
304 typedef struct pCodeOpImmd
307 int offset; /* low,med, or high byte of immediat value */
308 int index; /* add this to the immediate value */
309 unsigned _const:1; /* is in code space */
313 typedef struct pCodeOpLabel
319 typedef struct pCodeOpReg
321 pCodeOp pcop; // Can be either GPR or SFR
322 int rIdx; // Index into the register table
324 int instance; // byte # of Multi-byte registers
328 typedef struct pCodeOpRegBit
330 pCodeOpReg pcor; // The Register containing this bit
331 int bit; // 0-7 bit number.
332 PIC_OPTYPE subtype; // The type of this register.
333 unsigned int inBitSpace: 1; /* True if in bit space, else
334 just a bit of a register */
338 typedef struct pCodeOpWild
342 struct pCodeWildBlock *pcwb;
344 int id; /* index into an array of char *'s that will match
345 * the wild card. The array is in *pcp. */
346 pCodeOp *subtype; /* Pointer to the Operand type into which this wild
347 * card will be expanded */
348 pCodeOp *matched; /* When a wild matches, we'll store a pointer to the
349 * opcode we matched */
354 /*************************************************
357 Here is the basic build block of a PIC instruction.
358 Each pic instruction will get allocated a pCode.
359 A linked list of pCodes makes a program.
361 **************************************************/
367 struct pCode *prev; // The pCode objects are linked together
368 struct pCode *next; // in doubly linked lists.
370 int seq; // sequence number
372 struct pBlock *pb; // The pBlock that contains this pCode.
374 /* "virtual functions"
375 * The pCode structure is like a base class
376 * in C++. The subsequent structures that "inherit"
377 * the pCode structure will initialize these function
378 * pointers to something useful */
379 // void (*analyze) (struct pCode *_this);
380 void (*destruct)(struct pCode *_this);
381 void (*print) (FILE *of,struct pCode *_this);
386 /*************************************************
388 **************************************************/
390 typedef struct pCodeComment
399 /*************************************************
402 The Flow object is used as marker to separate
403 the assembly code into contiguous chunks. In other
404 words, everytime an instruction cause or potentially
405 causes a branch, a Flow object will be inserted into
406 the pCode chain to mark the beginning of the next
408 **************************************************/
410 typedef struct pCodeFlow
415 pCode *end; /* Last pCode in this flow. Note that
416 the first pCode is pc.next */
418 set **uses; /* map the pCode instruction inCond and outCond conditions
419 * in this array of set's. The reason we allocate an
420 * array of pointers instead of declaring each type of
421 * usage is because there are port dependent usage definitions */
422 int nuses; /* number of uses sets */
424 set *from; /* flow blocks that can send control to this flow block */
425 set *to; /* flow blocks to which this one can send control */
427 int inCond; /* Input conditions - stuff assumed defined at entry */
428 int outCond; /* Output conditions - stuff modified by flow block */
432 /*************************************************
435 Here we describe all the facets of a PIC instruction
436 (expansion for the 18cxxx is also provided).
438 **************************************************/
440 typedef struct pCodeInstruction
445 PIC_OPCODE op; // The opcode of the instruction.
447 char const * const mnemonic; // Pointer to mnemonic string
449 pBranch *from; // pCodes that execute before this one
450 pBranch *to; // pCodes that execute after
451 pBranch *label; // pCode instructions that have labels
453 pCodeOp *pcop; /* Operand, if this instruction has one */
455 pCodeFlow *pcflow; /* flow block to which this instruction belongs */
457 unsigned int num_ops; /* Number of operands (0,1,2 for mid range pics) */
458 unsigned int isModReg: 1; /* If destination is W or F, then 1==F */
459 unsigned int isBitInst: 1; /* e.g. BCF */
460 unsigned int isBranch: 1; /* True if this is a branching instruction */
461 unsigned int isSkip: 1; /* True if this is a skip instruction */
463 PIC_OPCODE inverted_op; /* Opcode of instruction that's the opposite of this one */
464 unsigned int inCond; // Input conditions for this instruction
465 unsigned int outCond; // Output conditions for this instruction
470 /*************************************************
472 **************************************************/
474 typedef struct pCodeLabel
484 /*************************************************
486 **************************************************/
488 typedef struct pCodeFunction
494 char *fname; /* If NULL, then this is the end of
495 a function. Otherwise, it's the
496 start and the name is contained
499 pBranch *from; // pCodes that execute before this one
500 pBranch *to; // pCodes that execute after
501 pBranch *label; // pCode instructions that have labels
506 /*************************************************
508 **************************************************/
510 typedef struct pCodeWild
513 pCodeInstruction pci;
515 int id; /* Index into the wild card array of a peepBlock
516 * - this wild card will get expanded into that pCode
517 * that is stored at this index */
519 /* Conditions on wild pcode instruction */
520 int mustBeBitSkipInst:1;
521 int mustNotBeBitSkipInst:1;
522 int invertBitSkipInst:1;
524 pCodeOp *operand; // Optional operand
525 pCodeOp *label; // Optional label
529 /*************************************************
532 Here are PIC program snippets. There's a strong
533 correlation between the eBBlocks and pBlocks.
534 SDCC subdivides a C program into managable chunks.
535 Each chunk becomes a eBBlock and ultimately in the
538 **************************************************/
540 typedef struct pBlock
542 memmap *cmemmap; /* The snippet is from this memmap */
543 char dbName; /* if cmemmap is NULL, then dbName will identify the block */
544 pCode *pcHead; /* A pointer to the first pCode in a link list of pCodes */
545 pCode *pcTail; /* A pointer to the last pCode in a link list of pCodes */
547 struct pBlock *next; /* The pBlocks will form a doubly linked list */
550 set *function_entries; /* dll of functions in this pblock */
555 unsigned visited:1; /* set true if traversed in call tree */
557 unsigned seq; /* sequence number of this pBlock */
561 /*************************************************
564 The collection of pBlock program snippets are
565 placed into a linked list that is implemented
566 in the pFile structure.
568 The pcode optimizer will parse the pFile.
570 **************************************************/
574 pBlock *pbHead; /* A pointer to the first pBlock */
575 pBlock *pbTail; /* A pointer to the last pBlock */
577 pBranch *functions; /* A SLL of functions in this pFile */
583 /*************************************************
586 The pCodeWildBlock object keeps track of the wild
587 variables, operands, and opcodes that exist in
589 **************************************************/
590 typedef struct pCodeWildBlock {
592 struct pCodePeep *pcp; // pointer back to ... I don't like this...
594 int nvars; // Number of wildcard registers in target.
595 char **vars; // array of pointers to them
597 int nops; // Number of wildcard operands in target.
598 pCodeOp **wildpCodeOps; // array of pointers to the pCodeOp's.
600 int nwildpCodes; // Number of wildcard pCodes in target/replace
601 pCode **wildpCodes; // array of pointers to the pCode's.
605 /*************************************************
608 The pCodePeep object mimics the peep hole optimizer
609 in the main SDCC src (e.g. SDCCpeeph.c). Essentially
610 there is a target pCode chain and a replacement
611 pCode chain. The target chain is compared to the
612 pCode that is generated by gen.c. If a match is
613 found then the pCode is replaced by the replacement
615 **************************************************/
616 typedef struct pCodePeep {
617 pCodeWildBlock target; // code we'd like to optimize
618 pCodeWildBlock replace; // and this is what we'll optimize it with.
621 //pBlock replace; // and this is what we'll optimize it with.
625 /* (Note: a wildcard register is a place holder. Any register
626 * can be replaced by the wildcard when the pcode is being
627 * compared to the target. */
629 /* Post Conditions. A post condition is a condition that
630 * must be either true or false before the peep rule is
631 * accepted. For example, a certain rule may be accepted
632 * if and only if the Z-bit is not used as an input to
633 * the subsequent instructions in a pCode chain.
635 unsigned int postFalseCond;
636 unsigned int postTrueCond;
640 /*************************************************
642 pCode peep command definitions
644 Here are some special commands that control the
645 way the peep hole optimizer behaves
647 **************************************************/
649 enum peepCommandTypes{
656 /*************************************************
657 peepCommand structure stores the peep commands.
659 **************************************************/
661 typedef struct peepCommand {
667 /*************************************************
670 **************************************************/
671 #define PCODE(x) ((pCode *)(x))
672 #define PCI(x) ((pCodeInstruction *)(x))
673 #define PCL(x) ((pCodeLabel *)(x))
674 #define PCF(x) ((pCodeFunction *)(x))
675 #define PCFL(x) ((pCodeFlow *)(x))
676 #define PCW(x) ((pCodeWild *)(x))
678 #define PCOP(x) ((pCodeOp *)(x))
679 //#define PCOB(x) ((pCodeOpBit *)(x))
680 #define PCOL(x) ((pCodeOpLit *)(x))
681 #define PCOI(x) ((pCodeOpImmd *)(x))
682 #define PCOLAB(x) ((pCodeOpLabel *)(x))
683 #define PCOR(x) ((pCodeOpReg *)(x))
684 #define PCORB(x) ((pCodeOpRegBit *)(x))
685 #define PCOW(x) ((pCodeOpWild *)(x))
687 #define PBR(x) ((pBranch *)(x))
689 #define PCWB(x) ((pCodeWildBlock *)(x))
691 /*-----------------------------------------------------------------*
693 *-----------------------------------------------------------------*/
695 pCode *newpCode (PIC_OPCODE op, pCodeOp *pcop); // Create a new pCode given an operand
696 pCode *newpCodeCharP(char *cP); // Create a new pCode given a char *
697 pCode *newpCodeFunction(char *g, char *f); // Create a new function
698 pCode *newpCodeLabel(char *name,int key); // Create a new label given a key
699 pBlock *newpCodeChain(memmap *cm,char c, pCode *pc); // Create a new pBlock
700 void printpBlock(FILE *of, pBlock *pb); // Write a pBlock to a file
701 void printpCode(FILE *of, pCode *pc); // Write a pCode to a file
702 void addpCode2pBlock(pBlock *pb, pCode *pc); // Add a pCode to a pBlock
703 void addpBlock(pBlock *pb); // Add a pBlock to a pFile
704 void copypCode(FILE *of, char dbName); // Write all pBlocks with dbName to *of
705 void movepBlock2Head(char dbName); // move pBlocks around
706 void AnalyzepCode(char dbName);
707 void OptimizepCode(char dbName);
708 void printCallTree(FILE *of);
709 void pCodePeepInit(void);
710 void pBlockConvert2ISR(pBlock *pb);
712 pCodeOp *newpCodeOpLabel(char *name, int key);
713 pCodeOp *newpCodeOpImmd(char *name, int offset, int index, int code_space);
714 pCodeOp *newpCodeOpLit(int lit);
715 pCodeOp *newpCodeOpBit(char *name, int bit,int inBitSpace);
716 pCodeOp *newpCodeOpRegFromStr(char *name);
717 pCodeOp *newpCodeOp(char *name, PIC_OPTYPE p);
718 pCodeOp *pCodeOpCopy(pCodeOp *pcop);
720 extern void pcode_test(void);
722 /*-----------------------------------------------------------------*
724 *-----------------------------------------------------------------*/
726 extern pCodeOpReg pc_status;
727 extern pCodeOpReg pc_intcon;
728 extern pCodeOpReg pc_indf;
729 extern pCodeOpReg pc_fsr;
730 extern pCodeOpReg pc_pcl;
731 extern pCodeOpReg pc_pclath;
732 extern pCodeOpReg pc_kzero;
733 extern pCodeOpReg pc_wsave; /* wsave and ssave are used to save W and the Status */
734 extern pCodeOpReg pc_ssave; /* registers during an interrupt */
737 #endif // __PCODE_H__
projects / fw / sdcc / blob