📄 cc4.c
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/*
** Small-C Compiler -- Part 4 -- Back End.
** Copyright 1982, 1983, 1985, 1988 J. E. Hendrix
** All rights reserved.
*/
#include <stdio.h>
#include "cc.h"
/* #define DISOPT */ /* display optimizations values */
/*************************** externals ****************************/
extern char
*cptr, *macn, *litq, *symtab, optimize, ssname[NAMESIZE];
extern int
*stage, litlab, litptr, csp, output, oldseg, usexpr,
*snext, *stail, *slast;
/***************** optimizer command definitions ******************/
/* -- p-codes must not overlap these */
#define any 0x00FF /* matches any p-code */
#define _pop 0x00FE /* matches if corresponding POP2 exists */
#define pfree 0x00FD /* matches if pri register free */
#define sfree 0x00FC /* matches if sec register free */
#define comm 0x00FB /* matches if registers are commutative */
/* -- these digits are reserved for n */
#define go 0x0100 /* go n entries */
#define gc 0x0200 /* get code from n entries away */
#define gv 0x0300 /* get value from n entries away */
#define sum 0x0400 /* add value from nth entry away */
#define neg 0x0500 /* negate the value */
#define ife 0x0600 /* if value == n do commands to next 0 */
#define ifl 0x0700 /* if value < n do commands to next 0 */
#define swv 0x0800 /* swap value with value n entries away */
#define topop 0x0900 /* moves |code and current value to POP2 */
#define p1 0x0001 /* plus 1 */
#define p2 0x0002 /* plus 2 */
#define p3 0x0003 /* plus 3 */
#define p4 0x0004 /* plus 4 */
#define m1 0x00FF /* minus 1 */
#define m2 0x00FE /* minus 2 */
#define m3 0x00FD /* minus 3 */
#define m4 0x00FC /* minus 4 */
#define PRI 0030 /* primary register bits */
#define SEC 0003 /* secondary register bits */
#define USES 0011 /* use register contents */
#define ZAPS 0022 /* zap register contents */
#define PUSHES 0100 /* pushes onto the stack */
#define COMMUTES 0200 /* commutative p-code */
/******************** optimizer command lists *********************/
int
seq00[] = {0,ADD12,MOVE21,0, /* ADD21 */
go|p1,ADD21,0},
seq01[] = {0,ADD1n,0, /* rINC1 or rDEC1 ? */
ifl|m2,0,ifl|0,rDEC1,neg,0,ifl|p3,rINC1,0,0},
seq02[] = {0,ADD2n,0, /* rINC2 or rDEC2 ? */
ifl|m2,0,ifl|0,rDEC2,neg,0,ifl|p3,rINC2,0,0},
seq03[] = {0,rDEC1,PUTbp1,rINC1,0, /* SUBbpn or DECbp */
go|p2,ife|p1,DECbp,0,SUBbpn,0},
seq04[] = {0,rDEC1,PUTwp1,rINC1,0, /* SUBwpn or DECwp */
go|p2,ife|p1,DECwp,0,SUBwpn,0},
seq05[] = {0,rDEC1,PUTbm1,rINC1,0, /* SUB_m_ COMMAn */
go|p1,SUB_m_,go|p1,COMMAn,go|m1,0},
seq06[] = {0,rDEC1,PUTwm1,rINC1,0, /* SUB_m_ COMMAn */
go|p1,SUB_m_,go|p1,COMMAn,go|m1,0},
seq07[] = {0,GETw1m,GETw2n,ADD12,MOVE21,GETb1p,0, /* GETw2m GETb1p */
go|p4,gv|m3,go|m1,GETw2m,gv|m3,0},
seq08[] = {0,GETw1m,GETw2n,ADD12,MOVE21,GETb1pu,0, /* GETw2m GETb1pu */
go|p4,gv|m3,go|m1,GETw2m,gv|m3,0},
seq09[] = {0,GETw1m,GETw2n,ADD12,MOVE21,GETw1p,0, /* GETw2m GETw1p */
go|p4,gv|m3,go|m1,GETw2m,gv|m3,0},
seq10[] = {0,GETw1m,GETw2m,SWAP12,0, /* GETw2m GETw1m */
go|p2,GETw1m,gv|m1,go|m1,gv|m1,0},
seq11[] = {0,GETw1m,MOVE21,0, /* GETw2m */
go|p1,GETw2m,gv|m1,0},
seq12[] = {0,GETw1m,PUSH1,pfree,0, /* PUSHm */
go|p1,PUSHm,gv|m1,0},
seq13[] = {0,GETw1n,PUTbm1,pfree,0, /* PUT_m_ COMMAn */
PUT_m_,go|p1,COMMAn,go|m1,swv|p1,0},
seq14[] = {0,GETw1n,PUTwm1,pfree,0, /* PUT_m_ COMMAn */
PUT_m_,go|p1,COMMAn,go|m1,swv|p1,0},
seq15[] = {0,GETw1p,PUSH1,pfree,0, /* PUSHp */
go|p1,PUSHp,gv|m1,0},
seq16[] = {0,GETw1s,GETw2n,ADD12,MOVE21,0, /* GETw2s ADD2n */
go|p3,ADD2n,gv|m2,go|m1,GETw2s,gv|m2,0},
seq17[] = {0,GETw1s,GETw2s,SWAP12,0, /* GETw2s GETw1s */
go|p2,GETw1s,gv|m1,go|m1,GETw2s,gv|m1,0},
seq18[] = {0,GETw1s,MOVE21,0, /* GETw2s */
go|p1,GETw2s,gv|m1,0},
seq19[] = {0,GETw2m,GETw1n,SWAP12,SUB12,0, /* GETw1m SUB1n */
go|p3,SUB1n,gv|m2,go|m1,GETw1m,gv|m2,0},
seq20[] = {0,GETw2n,ADD12,0, /* ADD1n */
go|p1,ADD1n,gv|m1,0},
seq21[] = {0,GETw2s,GETw1n,SWAP12,SUB12,0, /* GETw1s SUB1n */
go|p3,SUB1n,gv|m2,go|m1,GETw1s,gv|m2,0},
seq22[] = {0,rINC1,PUTbm1,rDEC1,0, /* ADDm_ COMMAn */
go|p1,ADDm_,go|p1,COMMAn,go|m1,0},
seq23[] = {0,rINC1,PUTwm1,rDEC1,0, /* ADDm_ COMMAn */
go|p1,ADDm_,go|p1,COMMAn,go|m1,0},
seq24[] = {0,rINC1,PUTbp1,rDEC1,0, /* ADDbpn or INCbp */
go|p2,ife|p1,INCbp,0,ADDbpn,0},
seq25[] = {0,rINC1,PUTwp1,rDEC1,0, /* ADDwpn or INCwp */
go|p2,ife|p1,INCwp,0,ADDwpn,0},
seq26[] = {0,MOVE21,GETw1n,SWAP12,SUB12,0, /* SUB1n */
go|p3,SUB1n,gv|m2,0},
seq27[] = {0,MOVE21,GETw1n,comm,0, /* GETw2n comm */
go|p1,GETw2n,0},
seq28[] = {0,POINT1m,GETw2n,ADD12,MOVE21,0, /* POINT2m_ PLUSn */
go|p3,PLUSn,gv|m2,go|m1,POINT2m_,gv|m2,0},
seq29[] = {0,POINT1m,MOVE21,pfree,0, /* POINT2m */
go|p1,POINT2m,gv|m1,0},
seq30[] = {0,POINT1m,PUSH1,pfree,_pop,0, /* ... POINT2m */
topop|POINT2m,go|p2,0},
seq31[] = {0,POINT1s,GETw2n,ADD12,MOVE21,0, /* POINT2s */
sum|p1,go|p3,POINT2s,gv|m3,0},
seq32[] = {0,POINT1s,PUSH1,MOVE21,0, /* POINT2s PUSH2 */
go|p1,POINT2s,gv|m1,go|p1,PUSH2,go|m1,0},
seq33[] = {0,POINT1s,PUSH1,pfree,_pop,0, /* ... POINT2s */
topop|POINT2s,go|p2,0},
seq34[] = {0,POINT1s,MOVE21,0, /* POINT2s */
go|p1,POINT2s,gv|m1,0},
seq35[] = {0,POINT2m,GETb1p,sfree,0, /* GETb1m */
go|p1,GETb1m,gv|m1,0},
seq36[] = {0,POINT2m,GETb1pu,sfree,0, /* GETb1mu */
go|p1,GETb1mu,gv|m1,0},
seq37[] = {0,POINT2m,GETw1p,sfree,0, /* GETw1m */
go|p1,GETw1m,gv|m1,0},
seq38[] = {0,POINT2m_,PLUSn,GETw1p,sfree,0, /* GETw1m_ PLUSn */
go|p2,gc|m1,gv|m1,go|m1,GETw1m_,gv|m1,0},
seq39[] = {0,POINT2s,GETb1p,sfree,0, /* GETb1s */
sum|p1,go|p1,GETb1s,gv|m1,0},
seq40[] = {0,POINT2s,GETb1pu,sfree,0, /* GETb1su */
sum|p1,go|p1,GETb1su,gv|m1,0},
seq41[] = {0,POINT2s,GETw1p,PUSH1,pfree,0, /* PUSHs */
sum|p1,go|p2,PUSHs,gv|m2,0},
seq42[] = {0,POINT2s,GETw1p,sfree,0, /* GETw1s */
sum|p1,go|p1,GETw1s,gv|m1,0},
seq43[] = {0,PUSH1,any,POP2,0, /* MOVE21 any */
go|p2,gc|m1,gv|m1,go|m1,MOVE21,0},
seq44[] = {0,PUSHm,_pop,0, /* ... GETw2m */
topop|GETw2m,go|p1,0},
seq45[] = {0,PUSHp,any,POP2,0, /* GETw2p ... */
go|p2,gc|m1,gv|m1,go|m1,GETw2p,gv|m1,0},
seq46[] = {0,PUSHs,_pop,0, /* ... GETw2s */
topop|GETw2s,go|p1,0},
seq47[] = {0,SUB1n,0, /* rDEC1 or rINC1 ? */
ifl|m2,0,ifl|0,rINC1,neg,0,ifl|p3,rDEC1,0,0};
#define HIGH_SEQ 47
int seq[HIGH_SEQ + 1];
setseq() {
seq[ 0] = seq00; seq[ 1] = seq01; seq[ 2] = seq02; seq[ 3] = seq03;
seq[ 4] = seq04; seq[ 5] = seq05; seq[ 6] = seq06; seq[ 7] = seq07;
seq[ 8] = seq08; seq[ 9] = seq09; seq[10] = seq10; seq[11] = seq11;
seq[12] = seq12; seq[13] = seq13; seq[14] = seq14; seq[15] = seq15;
seq[16] = seq16; seq[17] = seq17; seq[18] = seq18; seq[19] = seq19;
seq[20] = seq20; seq[21] = seq21; seq[22] = seq22; seq[23] = seq23;
seq[24] = seq24; seq[25] = seq25; seq[26] = seq26; seq[27] = seq27;
seq[28] = seq28; seq[29] = seq29; seq[30] = seq30; seq[31] = seq31;
seq[32] = seq32; seq[33] = seq33; seq[34] = seq34; seq[35] = seq35;
seq[36] = seq36; seq[37] = seq37; seq[38] = seq38; seq[39] = seq39;
seq[40] = seq40; seq[41] = seq41; seq[42] = seq42; seq[43] = seq43;
seq[44] = seq44; seq[45] = seq45; seq[46] = seq46; seq[47] = seq47;
}
/***************** assembly-code strings ******************/
int code[PCODES];
/*
** First byte contains flag bits indicating:
** the value in ax is needed (010) or zapped (020)
** the value in bx is needed (001) or zapped (002)
*/
setcodes() {
setseq();
code[ADD12] = "\211ADD AX,BX\n";
code[ADD1n] = "\010?ADD AX,<n>\n??";
code[ADD21] = "\211ADD BX,AX\n";
code[ADD2n] = "\010?ADD BX,<n>\n??";
code[ADDbpn] = "\001ADD BYTE PTR [BX],<n>\n";
code[ADDwpn] = "\001ADD WORD PTR [BX],<n>\n";
code[ADDm_] = "\000ADD <m>";
code[ADDSP] = "\000?ADD SP,<n>\n??";
code[AND12] = "\211AND AX,BX\n";
code[ANEG1] = "\010NEG AX\n";
code[ARGCNTn] = "\000?MOV CL,<n>?XOR CL,CL?\n";
code[ASL12] = "\011MOV CX,AX\nMOV AX,BX\nSAL AX,CL\n";
code[ASR12] = "\011MOV CX,AX\nMOV AX,BX\nSAR AX,CL\n";
code[CALL1] = "\010CALL AX\n";
code[CALLm] = "\020CALL <m>\n";
code[BYTE_] = "\000 DB ";
code[BYTEn] = "\000 DB <n>\n";
code[BYTEr0] = "\000 DB <n> DUP(0)\n";
code[COM1] = "\010NOT AX\n";
code[COMMAn] = "\000,<n>\n";
code[DBL1] = "\010SHL AX,1\n";
code[DBL2] = "\001SHL BX,1\n";
code[DECbp] = "\001DEC BYTE PTR [BX]\n";
code[DECwp] = "\001DEC WORD PTR [BX]\n";
code[DIV12] = "\011CWD\nIDIV BX\n"; /* see gen() */
code[DIV12u] = "\011XOR DX,DX\nDIV BX\n"; /* see gen() */
code[ENTER] = "\100PUSH BP\nMOV BP,SP\n";
code[EQ10f] = "\010OR AX,AX\nJE $+5\nJMP _<n>\n";
code[EQ12] = "\211CALL __eq\n";
code[GE10f] = "\010OR AX,AX\nJGE $+5\nJMP _<n>\n";
code[GE12] = "\011CALL __ge\n";
code[GE12u] = "\011CALL __uge\n";
code[GETb1m] = "\020MOV AL,<m>\nCBW\n";
code[GETb1mu] = "\020MOV AL,<m>\nXOR AH,AH\n";
code[GETb1p] = "\021MOV AL,?<n>??[BX]\nCBW\n"; /* see gen() */
code[GETb1pu] = "\021MOV AL,?<n>??[BX]\nXOR AH,AH\n"; /* see gen() */
code[GETb1s] = "\020MOV AL,<n>[BP]\nCBW\n";
code[GETb1su] = "\020MOV AL,<n>[BP]\nXOR AH,AH\n";
code[GETw1m] = "\020MOV AX,<m>\n";
code[GETw1m_] = "\020MOV AX,<m>";
code[GETw1n] = "\020?MOV AX,<n>?XOR AX,AX?\n";
code[GETw1p] = "\021MOV AX,?<n>??[BX]\n"; /* see gen() */
code[GETw1s] = "\020MOV AX,<n>[BP]\n";
code[GETw2m] = "\002MOV BX,<m>\n";
code[GETw2n] = "\002?MOV BX,<n>?XOR BX,BX?\n";
code[GETw2p] = "\021MOV BX,?<n>??[BX]\n";
code[GETw2s] = "\002MOV BX,<n>[BP]\n";
code[GT10f] = "\010OR AX,AX\nJG $+5\nJMP _<n>\n";
code[GT12] = "\010CALL __gt\n";
code[GT12u] = "\011CALL __ugt\n";
code[INCbp] = "\001INC BYTE PTR [BX]\n";
code[INCwp] = "\001INC WORD PTR [BX]\n";
code[WORD_] = "\000 DW ";
code[WORDn] = "\000 DW <n>\n";
code[WORDr0] = "\000 DW <n> DUP(0)\n";
code[JMPm] = "\000JMP _<n>\n";
code[LABm] = "\000_<n>:\n";
code[LE10f] = "\010OR AX,AX\nJLE $+5\nJMP _<n>\n";
code[LE12] = "\011CALL __le\n";
code[LE12u] = "\011CALL __ule\n";
code[LNEG1] = "\010CALL __lneg\n";
code[LT10f] = "\010OR AX,AX\nJL $+5\nJMP _<n>\n";
code[LT12] = "\011CALL __lt\n";
code[LT12u] = "\011CALL __ult\n";
code[MOD12] = "\011CWD\nIDIV BX\nMOV AX,DX\n"; /* see gen() */
code[MOD12u] = "\011XOR DX,DX\nDIV BX\nMOV AX,DX\n"; /* see gen() */
code[MOVE21] = "\012MOV BX,AX\n";
code[MUL12] = "\211IMUL BX\n";
code[MUL12u] = "\211MUL BX\n";
code[NE10f] = "\010OR AX,AX\nJNE $+5\nJMP _<n>\n";
code[NE12] = "\211CALL __ne\n";
code[NEARm] = "\000 DW _<n>\n";
code[OR12] = "\211OR AX,BX\n";
code[PLUSn] = "\000?+<n>??\n";
code[POINT1l] = "\020MOV AX,OFFSET _<l>+<n>\n";
code[POINT1m] = "\020MOV AX,OFFSET <m>\n";
code[POINT1s] = "\020LEA AX,<n>[BP]\n";
code[POINT2m] = "\002MOV BX,OFFSET <m>\n";
code[POINT2m_]= "\002MOV BX,OFFSET <m>";
code[POINT2s] = "\002LEA BX,<n>[BP]\n";
code[POP2] = "\002POP BX\n";
code[PUSH1] = "\110PUSH AX\n";
code[PUSH2] = "\101PUSH BX\n";
code[PUSHm] = "\100PUSH <m>\n";
code[PUSHp] = "\100PUSH ?<n>??[BX]\n";
code[PUSHs] = "\100PUSH ?<n>??[BP]\n";
code[PUT_m_] = "\000MOV <m>";
code[PUTbm1] = "\010MOV <m>,AL\n";
code[PUTbp1] = "\011MOV [BX],AL\n";
code[PUTwm1] = "\010MOV <m>,AX\n";
code[PUTwp1] = "\011MOV [BX],AX\n";
code[rDEC1] = "\010#DEC AX\n#";
code[rDEC2] = "\010#DEC BX\n#";
code[REFm] = "\000_<n>";
code[RETURN] = "\000?MOV SP,BP\n??POP BP\nRET\n";
code[rINC1] = "\010#INC AX\n#";
code[rINC2] = "\010#INC BX\n#";
code[SUB_m_] = "\000SUB <m>";
code[SUB12] = "\011SUB AX,BX\n"; /* see gen() */
code[SUB1n] = "\010?SUB AX,<n>\n??";
code[SUBbpn] = "\001SUB BYTE PTR [BX],<n>\n";
code[SUBwpn] = "\001SUB WORD PTR [BX],<n>\n";
code[SWAP12] = "\011XCHG AX,BX\n";
code[SWAP1s] = "\012POP BX\nXCHG AX,BX\nPUSH BX\n";
code[SWITCH] = "\012CALL __switch\n";
code[XOR12] = "\211XOR AX,BX\n";
}
/***************** code generation functions *****************/
/*
** print all assembler info before any code is generated
** and ensure that the segments appear in the correct order.
*/
header() {
toseg(CODESEG);
outline("extrn __eq: near");
outline("extrn __ne: near");
outline("extrn __le: near");
outline("extrn __lt: near");
outline("extrn __ge: near");
outline("extrn __gt: near");
outline("extrn __ule: near");
outline("extrn __ult: near");
outline("extrn __uge: near");
outline("extrn __ugt: near");
outline("extrn __lneg: near");
outline("extrn __switch: near");
outline("dw 0"); /* force non-zero code pointers, word alignment */
toseg(DATASEG);
outline("dw 0"); /* force non-zero data pointers, word alignment */
}
/*
** print any assembler stuff needed at the end
*/
trailer() {
char *cp;
cptr = STARTGLB;
while(cptr < ENDGLB) {
if(cptr[IDENT] == FUNCTION && cptr[CLASS] == AUTOEXT)
external(cptr + NAME, 0, FUNCTION);
cptr += SYMMAX;
}
if((cp = findglb("main")) && cp[CLASS]==STATIC)
external("_main", 0, FUNCTION);
toseg(NULL);
outline("END");
#ifdef DISOPT
{
int i, *count;
printf(";opt count\n");
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