mirror of
https://github.com/RevCurtisP/C02.git
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253 lines
5.5 KiB
C
253 lines
5.5 KiB
C
/***********************************
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* C02 Expression Parsing Routines *
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***********************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <string.h>
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#include <errno.h>
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#include "common.h"
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#include "asm.h"
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#include "parse.h"
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#include "vars.h"
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#include "label.h"
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#include "expr.h"
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/* Parse value (constant or identifier) *
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* Sets: value - the value (as a string) *
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* valtyp - value type */
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void prsval(int alwreg)
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{
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DEBUG("Parsing value\n", 0);
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skpspc();
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if (iscpre())
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prscon(); //Parse Constant
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else if (isalph()) {
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prsvar(alwreg); //Parse Variable
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}
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else
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expctd("constant or variable");
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DEBUG("Parsed value of type %d\n", valtyp);
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skpspc();
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}
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/* Parse array index *
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* Sets: value - array index or *
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* "" if no index defined */
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void prsidx()
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{
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expect('[');
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prsval(TRUE);
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DEBUG("Parsed array index '%s'\n", value);
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expect(']');
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}
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/* Check for, Parse, and Process index */
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void chkidx()
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{
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//DEBUG("Checking for Array Index with valtyp=%d\n", valtyp);
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if (valtyp == ARRAY) {
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prsidx();
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if (valtyp == CONSTANT) {
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strcat(term, "+");
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strcat(term, word);
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}
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else if (strcmp(value, "Y")==0)
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strcat(term, ",Y");
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else {
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if (strcmp(value, "A")==0)
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asmlin("TAX", "");
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else if (strcmp(value, "X")!=0)
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asmlin("LDX", value);
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strcat(term, ",X");
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}
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}
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}
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/* Parse term in expression *
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* Sets: term - the term (as a string) */
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void prstrm()
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{
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DEBUG("Parsing term\n", 0);
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prsval(FALSE);
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if (valtyp == FUNCTION) {
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ERROR("Function call only allowed in first term\n", 0, EXIT_FAILURE);
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}
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strcpy(term, value);
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DEBUG("Parsed term %s\n", term);
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chkidx(); //Check for Array Index
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//chkpst = ispopr(); //Check for Post-Op
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skpspc();
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}
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/* Compile Address Reference */
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void prcadr(int adract, char* symbol)
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{
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DEBUG("Processing address '%s'\n", word);
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strcpy(word,"#>");
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strcat(word,symbol);
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if (adract == 1) {
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asmlin("LDA", word);
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asmlin("PHA", "");
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}
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else
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asmlin("LDY", word);
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strcpy(word,"#<");
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strcat(word,symbol);
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if (adract == 1) {
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asmlin("LDA", word);
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asmlin("PHA", "");
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}
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else
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asmlin("LDX", word);
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}
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/* Parse and Compile Address of Operator */
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void prsadr(int adract)
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{
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DEBUG("Parsing address\n", 0);
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if (isnpre())
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prsnum(0xFFFF);
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else
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prsvar(FALSE);
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prcadr(adract, value); //Compile Address Reference
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}
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/* Parse and Create Anonymous String */
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void prsstr(adract)
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{
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DEBUG("Parsing anonymous string\n", 0);
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newlbl(vrname); //Generate Variable Name
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value[0] = 0; //Use Variable Size 0
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setvar(MTNONE, VTCHAR); //Set Variable Name, Type, and Size
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prsdts(); //Parse Data String
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setdat(); //Set Variable Data
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varcnt++; //Increment Variable Counter
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prcadr(adract, vrname); //Compile Address Reference
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}
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/* Check for and Process Address or String */
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int chkadr(adract)
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{
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DEBUG("Checking for Address or String\n", 0);
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int result = TRUE;
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if (look('&'))
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prsadr(adract);
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else if (match('"'))
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prsstr(adract);
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else
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result = FALSE;
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skpspc();
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return result;
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}
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/* Parse function call */
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void prsfnc(char trmntr)
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{
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DEBUG("Processing Function Call '%s'...\n", term);
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if (fnscnt >= MAXFNS)
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ERROR("Maximum Function Call Depth Exceeded", 0, EXIT_FAILURE);
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strcpy(fnstck[fnscnt++], term);
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skpchr(); //skip open paren
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CCMNT('(');
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if (!chkadr(0) && isxpre() || match('*')) {
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if (!look('*')) prsxpr(0);
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if (look(',')) {
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if (!chkadr(0)) {
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if (!look('*')) {
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prstrm();
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asmlin("LDY", term);
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}
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if (look(',')) {
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if (!look('*')) {
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prsval(FALSE);
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asmlin("LDX", value);
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}
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}
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}
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}
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}
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expect(')');
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expect(trmntr);
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asmlin("JSR", fnstck[--fnscnt]);
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skpspc();
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}
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/* Parse first term of expession *
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* First term can include function calls */
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void prsftm()
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{
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prsval(TRUE);
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DEBUG("Processing first term '%s'...\n", value);
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strcpy(term, value);
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if (valtyp == FUNCTION) {
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prsfnc(0); //Parse Expression Function
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return;
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}
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if (wordis("A"))
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return;
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if (wordis("X"))
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asmlin("TXA", "");
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else if (wordis("Y"))
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asmlin("TYA", "");
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else {
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chkidx(); //Check for Array Index
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asmlin("LDA", term);
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}
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}
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/* Process Arithmetic or Bitwise Operator *
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* and the term that follows it */
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void prcopr()
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{
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DEBUG("Processing operator '%c'\n", oper);
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switch(oper)
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{
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case '+':
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asmlin("CLC", "");
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asmlin("ADC", term);
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break;
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case '-':
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asmlin("SEC", "");
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asmlin("SBC", term);
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break;
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case '&':
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asmlin("AND", term);
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break;
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case '|':
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case '!': //For systems that don't have pipe in character set
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asmlin("ORA", term);
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break;
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case '^': //Looks like an up-arrow in some character sets
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asmlin("EOR", term);
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break;
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default:
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printf("Unrecognized operator '%c'\n", oper);
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exterr(EXIT_FAILURE);
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}
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oper = 0;
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}
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/* Parse and compile expression */
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void prsxpr(char trmntr)
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{
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DEBUG("Parsing expression\n", 0);
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skpspc();
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if (match('-')) {
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DEBUG("Processing unary minus", 0);
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asmlin("LDA", "#$00"); //Handle Unary Minus
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}
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else
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prsftm(); //Parse First Term
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skpspc();
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while (isoper())
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{
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prsopr(); //Parse Operator
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prstrm(); //Parse Term
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prcopr(); //Process Operator
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}
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expect(trmntr);
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}
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