mirror of https://github.com/RevCurtisP/C02.git
139 lines
4.6 KiB
C
139 lines
4.6 KiB
C
/************************************
|
|
* C02 Conditional Parsing Routines *
|
|
************************************/
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <ctype.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
#include "common.h"
|
|
#include "asm.h"
|
|
#include "parse.h"
|
|
#include "vars.h"
|
|
#include "expr.h"
|
|
#include "label.h"
|
|
#include "cond.h"
|
|
|
|
int cmprtr; //Encoded Comparison Operator
|
|
int cmpenc; //Encoded Comparator Character
|
|
|
|
/* Encode Comparison Operator Character *
|
|
* Args: Comparison Operator Character *
|
|
* Returns: Comparison Operator Bit Mask */
|
|
int enccmp(char c) {
|
|
int e;
|
|
DEBUG("cond.enccm: Encoding Comparison Character '%c'", c)
|
|
switch(c) {
|
|
case '=': e = 1; break;
|
|
case '<': e = 2; break;
|
|
case '>': e = 4; break;
|
|
default: e = 0;
|
|
}
|
|
if (e) { CCMNT(c); skpchr(); }
|
|
DETAIL(", encoded as %d\n", e);
|
|
return e;
|
|
}
|
|
|
|
/* Process and Compile Comparison Operator and *
|
|
* Args: comparator - Encoded Comparison Operator *
|
|
* Uses: term - Term Being Compared Against *
|
|
* label - Branch Target if Comparison is FALSE */
|
|
void prccmp(void) {
|
|
DEBUG("cond.prccmp: Processing comparator %d", cmprtr) DETAIL(" with REVCMP=%d\n", revcmp)
|
|
if (cmprtr > 7) { //Process Flag
|
|
cmprtr = (cmprtr ^ revcmp) & 1; //Apply Reversal
|
|
if (cmprtr) asmlin("BPL", cmplbl);
|
|
else asmlin("BMI", cmplbl);
|
|
return;
|
|
}
|
|
cmprtr = (cmprtr ^ revcmp) & 7; //Apply reversal
|
|
switch(cmprtr) {
|
|
case 0: // Raw Expression (Skip)
|
|
asmlin("BEQ", cmplbl); break;
|
|
case 1: // = or ==
|
|
asmlin("CMP", term); asmlin("BNE", cmplbl); break;
|
|
case 2: // <
|
|
asmlin("CMP", term); asmlin("BCS", cmplbl); break;
|
|
case 3: // <= or =<
|
|
asmlin("CLC", ""); asmlin("SBC", term); asmlin("BCS", cmplbl); break;
|
|
case 4: // >
|
|
asmlin("CLC", ""); asmlin("SBC", term); asmlin("BCC", cmplbl); break;
|
|
case 5: // >= or =>
|
|
asmlin("CMP", term); asmlin("BCC", cmplbl); break;
|
|
case 6: // <> or ><
|
|
asmlin("CMP", term); asmlin("BEQ", cmplbl); break;
|
|
case 7: // Raw Expression (Normal)
|
|
asmlin("BNE", cmplbl); break;
|
|
default:
|
|
ERROR("Unsupported comparison operator index %d\n", cmprtr, EXIT_FAILURE)
|
|
}
|
|
}
|
|
|
|
/* Parse Comparison */
|
|
void prscmp(int revrse) {
|
|
skpspc();
|
|
cmpenc = enccmp(nxtchr); //Encode Comparison Character
|
|
cmprtr = cmpenc; //Set Encoded Comparator
|
|
if (cmprtr) {
|
|
cmpenc = enccmp(nxtchr); //Encode Next Comparison Character
|
|
if (cmpenc != 0) cmprtr = cmprtr | cmpenc; //Combine Encoded Comparator
|
|
}
|
|
skpspc();
|
|
if (cmprtr) prstrm(FALSE, TRUE);
|
|
//prccmp(); - Do after check for logical operator
|
|
DEBUG("cond.prscmp: Parsed comparator %d\n", cmprtr)
|
|
}
|
|
|
|
/* Parse Flag Operator */
|
|
void prsflg(int revrse) {
|
|
DEBUG("cond.prsflg: Parsing Flag Operator '%c'\n", nxtchr)
|
|
if (match('+')) cmprtr = 8; //Bit 0 = 0
|
|
else if (match('-')) cmprtr = 9; //Bit 1 = 1
|
|
else expctd("Flag operator");
|
|
skpchr();
|
|
}
|
|
|
|
/* Parse Logical Operator *
|
|
* Sets: logops */
|
|
void prslop(void) {
|
|
DEBUG("cond.prslop: Checking for Logical Operator\n", 0)
|
|
logopr = LOPNONE;
|
|
skpspc();
|
|
if (isalph()) {
|
|
getwrd(); //Get Logical Operator
|
|
DEBUG("cond.prslop: Parsing Logical Operator %s\n", word)
|
|
if (wordis("AND")) logopr = LOPAND;
|
|
else if (wordis("OR")) logopr = LOPOR;
|
|
else ERROR("Encountered invalid token \"%s\"\n", word, EXIT_FAILURE)
|
|
}
|
|
DEBUG("cond.prslop: Set LOGOPR to %d\n", logopr)
|
|
}
|
|
|
|
/* Parse and Compile Conditional Expression *
|
|
* Condition = <expression> <comparator> <term> */
|
|
void prscnd(char trmntr, int revrse) {
|
|
DEBUG("cond.prscnd: Parsing condition with REVRSE=%d\n", revrse)
|
|
tmplbl[0] = 0;
|
|
do {
|
|
strcpy(cmplbl, cndlbl); DEBUG("cond.prscnd: Set CMPLBL to \"%s\"\n", cmplbl);
|
|
revcmp = revrse;
|
|
if (look('!')) revcmp = (revcmp) ? FALSE: TRUE;
|
|
DEBUG("cond.prscnd: Set REVCMP to %d\n", revcmp)
|
|
if (!look('.')) prsxpr(0);
|
|
if (look(':')) prsflg(revcmp); //Parse Flag Operator
|
|
else prscmp(revcmp); //Parse Comparison Operator
|
|
prslop(); //Parse Logical Operator
|
|
if (logopr == LOPOR) {
|
|
revcmp = (revcmp) ? FALSE: TRUE;
|
|
DEBUG("cond.prscnd: Set REVCMP to %d\n", revcmp)
|
|
}
|
|
if (logopr && revcmp) {
|
|
if (!tmplbl[0]) newlbl(tmplbl);
|
|
strcpy(cmplbl, tmplbl); DEBUG("cond.prscnd: Set CMPLBL to \"%s\"\n", cmplbl);
|
|
}
|
|
prccmp(); //Process Comparison/Flag Operator
|
|
} while (logopr);
|
|
if (tmplbl[0]) setlbl(tmplbl);
|
|
expect(trmntr);
|
|
}
|