+/*-*- indent-tabs-mode:nil -*- */
/* Copyright (C) 2007 Jeremy English <jhe@jeremyenglish.org>
*
* Permission to use, copy, modify, distribute, and sell this software and its
#include "asm6502.h"
+#ifdef DEBUGGER
+# define random rand
+#endif
+
typedef enum{
LEFT, RIGHT
} Side;
Bit16 value;
} Pointer;
-/* eprintf - Taken from "Practice of Programming" by Kernighan and Pike */
-static void eprintf(char *fmt, ...){
- va_list args;
-
- char *progname = "Assembler";
-
- fflush(stdout);
- if (progname != NULL)
- fprintf(stderr, "%s: ", progname);
-
- va_start(args, fmt);
- vfprintf(stderr, fmt, args);
- va_end(args);
-
- if (fmt[0] != '\0' && fmt[strlen(fmt) -1] == ':')
- fprintf(stderr, " %s", strerror(errno));
- fprintf(stderr, "\n");
- exit(2); /* conventional value for failed execution */
-}
-/* emalloc - Taken from "Practice of Programming" by Kernighan and
- Pike. If memory allocatiion fails the program will print a message
- an exit. */
static void *emalloc(size_t n) {
- void *p;
-
- p = malloc(n);
- if (p == NULL)
- eprintf("malloc of %u bytes failed:", n);
+ void *p = malloc(n);
+ if (! p) abort();
return p;
}
-/* ecalloc - Dose the same thing as emalloc just calls calloc instead. */
static void *ecalloc(uint32_t nelm, size_t nsize){
- void *p;
-
- p = calloc(nelm, nsize);
- if (p == NULL)
- eprintf("calloc of %u bytes failed:", nelm * nsize);
+ void *p = calloc(nelm, nsize);
+ if (!p) abort();
return p;
}
}
static void pushByte(machine_6502 *machine, Bit32 value ) {
- Bit32 address = 0x600 + machine->codeLen;
+ Bit32 address = machine->defaultCodePC;
checkAddress(address);
- machine->memory[0x600 + machine->codeLen] = value & 0xff;
+ machine->memory[address] = value & 0xff;
machine->codeLen++;
+ machine->defaultCodePC++;
}
/*
pointer->value = memReadByte(machine, PC);
return TRUE;
case INDIRECT_X:
- zp = memReadByte(machine, PC);
+ zp = memReadByte(machine, PC) + machine->regX;
pointer->addr = memReadByte(machine,zp) +
- (memReadByte(machine,zp+1)<<8) + machine->regX;
+ (memReadByte(machine,zp+1)<<8);
pointer->value = memReadByte(machine, pointer->addr);
return TRUE;
case INDIRECT_Y:
pointer->value = popByte(machine);
return TRUE;
case INDIRECT_X:
- zp = popByte(machine);
+ zp = popByte(machine) + machine->regX;
pointer->addr = memReadByte(machine,zp) +
- (memReadByte(machine,zp+1)<<8) + machine->regX;
+ (memReadByte(machine,zp+1)<<8);
pointer->value = memReadByte(machine, pointer->addr);
return TRUE;
case INDIRECT_Y:
}
+static void dismem(machine_6502 *machine, AddrMode adm, char *output){
+ Bit8 zp;
+ Bit16 n;
+ switch(adm){
+ case SINGLE:
+ *output = 0;
+ break;
+ case IMMEDIATE_LESS:
+ case IMMEDIATE_GREAT:
+ case IMMEDIATE_VALUE:
+ n = popByte(machine);
+ sprintf(output,"#$%x",n);
+ break;
+ case INDIRECT_X:
+ zp = popByte(machine);
+ n = memReadByte(machine,zp) +
+ (memReadByte(machine,zp+1)<<8);
+ sprintf(output,"($%x,x)",n);
+ break;
+ case INDIRECT_Y:
+ zp = popByte(machine);
+ n = memReadByte(machine,zp) +
+ (memReadByte(machine,zp+1)<<8);
+ sprintf(output,"($%x),y",n);
+ break;
+ case ABS_OR_BRANCH:
+ case ZERO:
+ n = popByte(machine);
+ sprintf(output,"$%x",n);
+ break;
+ case ZERO_X:
+ n = popByte(machine);
+ sprintf(output,"$%x,x",n);
+ break;
+ case ZERO_Y:
+ n = popByte(machine);
+ sprintf(output,"$%x,y",n);
+ break;
+ case ABS_VALUE:
+ n = popWord(machine);
+ sprintf(output,"$%x",n);
+ break;
+ case ABS_LABEL_X:
+ case ABS_X:
+ n = popWord(machine);
+ sprintf(output,"$%x,x",n);
+ break;
+ case ABS_LABEL_Y:
+ case ABS_Y:
+ n = popWord(machine);
+ sprintf(output,"$%x,x",n);
+ break;
+ case DCB_PARAM:
+ *output = 0;
+ break;
+ }
+}
+
/* manZeroNeg - Manage the negative and zero flags */
static void manZeroNeg(machine_6502 *machine, Bit8 value){
machine->regP = setBit(machine->regP, ZERO_FL, (value == 0));
static void jmpSBC(machine_6502 *machine, AddrMode adm){
Pointer ptr;
- Bit8 vflag;
+ /*Bit8 vflag;*/
Bit8 c = bitOn(machine->regP, CARRY_FL);
Bit16 tmp, w;
BOOL isValue = getValue(machine, adm, &ptr);
warnValue(isValue);
- vflag = (bitOn(machine->regA,NEGATIVE_FL) &&
- bitOn(ptr.value, NEGATIVE_FL));
+ /*vflag = (bitOn(machine->regA,NEGATIVE_FL) &&
+ bitOn(ptr.value, NEGATIVE_FL));*/
if (bitOn(machine->regP, DECIMAL_FL)) {
Bit8 ar = nibble(machine->regA, RIGHT);
Bit8 br = nibble(ptr.value, RIGHT);
Bit8 al = nibble(machine->regA, LEFT);
- Bit8 bl = nibble(machine->regA, LEFT);
+ Bit8 bl = nibble(ptr.value, LEFT);
tmp = 0xf + ar - br + c;
if ( tmp < 0x10){
static void assignOpCodes(Opcodes *opcodes){
#define SETOP(num, _name, _Imm, _ZP, _ZPX, _ZPY, _ABS, _ABSX, _ABSY, _INDX, _INDY, _SNGL, _BRA, _func) \
-{opcodes[num].name[4] = '\0'; \
+{opcodes[num].name[3] = '\0'; \
strncpy(opcodes[num].name, _name, 3); opcodes[num].Imm = _Imm; opcodes[num].ZP = _ZP; \
opcodes[num].ZPX = _ZPX; opcodes[num].ZPY = _ZPY; opcodes[num].ABS = _ABS; \
opcodes[num].ABSX = _ABSX; opcodes[num].ABSY = _ABSY; opcodes[num].INDX = _INDX; \
}
}
+/* isCmdChar() - Is this a valid character for a command. All of the
+ command are alpha except for the entry point code that is "*=" */
+static BOOL isCmdChar(char c){
+ return (isalpha(c) || c == '*' || c == '=');
+}
+
+
/* command() - parse a command from the source code. We pass along a
machine so the opcode can be validated. */
static BOOL command(machine_6502 *machine, char **s, char **cmd){
int i = 0;
skipSpace(s);
- for(;isalpha(**s) && i < MAX_CMD_LEN; (*s)++)
+ for(;isCmdChar(**s) && i < MAX_CMD_LEN; (*s)++)
(*cmd)[i++] = **s;
if (i == 0)
return TRUE; /* Could be a blank line. */
+ else if (strcmp(*cmd,"*=") == 0)
+ return TRUE; /* This is an entry point. */
else
return isCommand(machine,*cmd);
}
}
/* fileToBuffer() - Allocates a buffer and loads all of the file into memory. */
-static char *fileToBuffer(char *filename){
+static char *fileToBuffer(const char *filename){
const int defaultSize = 1024;
FILE *ifp;
int c;
int i = 0;
char *buffer = ecalloc(defaultSize,sizeof(char));
- if (buffer == NULL)
- eprintf("Could not allocate memory for buffer.");
+ if (!buffer) abort();
ifp = fopen(filename, "rb");
- if (ifp == NULL)
- eprintf("Could not open file.");
+ if (!ifp) return 0;
while((c = getc(ifp)) != EOF){
buffer[i++] = c;
size += defaultSize;
buffer = realloc(buffer, size);
if (buffer == NULL) {
- fclose(ifp);
- eprintf("Could not resize buffer.");
+ abort();
}
}
}
fclose(ifp);
buffer = realloc(buffer, i+2);
- if (buffer == NULL)
- eprintf("Could not resize buffer.");
+ if (!buffer) abort();
/* Make sure we have a line feed at the end */
buffer[i] = '\n';
buffer[i+1] = '\0';
machine->regX = 0;
machine->regY = 0;
machine->regP = setBit(machine->regP, FUTURE_FL, 1);
- machine->regPC = 0x600;
+ machine->defaultCodePC = machine->regPC = PROG_START;
machine->regSP = STACK_TOP;
machine->runForever = FALSE;
machine->labelPtr = 0;
fprintf(output,"%s\n",(i&1)?"--":"");
}
-void save_program(machine_6502 *machine, char *filename){
- FILE *ofp;
- Bit16 pc = 0x600;
- Bit16 end = pc + machine->codeLen;
- Bit16 n;
- ofp = fopen(filename, "w");
- if (ofp == NULL)
- eprintf("Could not open file.");
+/* XXX */
+/* void save_program(machine_6502 *machine, char *filename){ */
+/* FILE *ofp; */
+/* Bit16 pc = PROG_START; */
+/* Bit16 end = pc + machine->codeLen; */
+/* Bit16 n; */
+/* ofp = fopen(filename, "w"); */
+/* if (!ofp) abort(); */
- fprintf(ofp,"Bit8 prog[%d] =\n{",machine->codeLen);
- n = 1;
- while(pc < end)
- fprintf(ofp,"0x%.2x,%s",machine->memory[pc++],n++%10?" ":"\n");
- fseek(ofp,-2,SEEK_CUR);
- fprintf(ofp,"};\n");
+/* fprintf(ofp,"Bit8 prog[%d] =\n{",machine->codeLen); */
+/* n = 1; */
+/* while(pc < end) */
+/* fprintf(ofp,"0x%.2x,%s",machine->memory[pc++],n++%10?" ":"\n"); */
+/* fseek(ofp,-2,SEEK_CUR); */
+/* fprintf(ofp,"};\n"); */
- fclose(ofp);
-}
+/* fclose(ofp); */
+/* } */
static BOOL translate(Opcodes *op,Param *param, machine_6502 *machine){
switch(param->type){
case IMMEDIATE_GREAT:
if (op->Imm) {
pushByte(machine, op->Imm);
- pushByte(machine, param->lbladdr / 0xFF);
+ pushByte(machine, param->lbladdr >> 8);
break;
}
else {
else {
if (op->BRA) {
pushByte(machine, op->BRA);
- if (param->lbladdr < (machine->codeLen + 0x600))
- pushByte(machine,
- (0xff - (machine->codeLen-param->lbladdr)) & 0xff);
- else
- pushByte(machine,
- (param->lbladdr - machine->codeLen-1) & 0xff);
+ {
+ int diff = abs(param->lbladdr - machine->defaultCodePC);
+ int backward = (param->lbladdr < machine->defaultCodePC);
+ pushByte(machine, (backward) ? 0xff - diff : diff - 1);
+ }
}
else {
fprintf(stderr,"%s does not take BRANCH parameters.\n",op->name);
machine_6502 *machine;
machine = args;
if (isBlank(asmline->command)) return TRUE;
-
- if (strcmp("DCB",asmline->command) == 0){
+ if (strcmp("*=",asmline->command) == 0){
+ machine->defaultCodePC = asmline->param->value[0];
+ }
+ else if (strcmp("DCB",asmline->command) == 0){
int i;
for(i = 0; i < asmline->param->vp; i++)
pushByte(machine, asmline->param->value[i]);
static BOOL indexLabels(AsmLine *asmline, void *arg){
machine_6502 *machine;
int thisPC;
+ Bit16 oldDefault;
machine = arg;
+ oldDefault = machine->defaultCodePC;
thisPC = machine->regPC;
/* Figure out how many bytes this instruction takes */
machine->codeLen = 0;
+
if ( ! compileLine(asmline, machine) ){
return FALSE;
}
- machine->regPC += machine->codeLen;
+
+ /* If the machine's defaultCodePC has changed then we encountered a
+ *= which changes the load address. We need to initials our code
+ *counter with the current default. */
+ if (oldDefault == machine->defaultCodePC){
+ machine->regPC += machine->codeLen;
+ }
+ else {
+ machine->regPC = machine->defaultCodePC;
+ /*oldDefault = machine->defaultCodePC;*/
+ }
+
if (asmline->labelDecl) {
asmline->label->addr = thisPC;
}
AsmLine *asmlist;
reset(machine);
- machine->regPC = 0x600;
+ machine->defaultCodePC = machine->regPC = PROG_START;
asmlist = parseAssembly(machine, &codeOk, code);
if(codeOk){
return FALSE;
/* update label references */
linkLabels(asmlist);
+
+#if 0 /* prints out some debugging information */
+ {
+ AsmLine *p;
+ if(asmlist != NULL){
+ for (p = asmlist; p != NULL; p = p->next)
+ fprintf(stderr,"%s lbl: %s addr: %d ParamLbl: %s ParamAddr: %d\n",
+ p->command, p->label->label, p->label->addr,
+ p->param->label, p->param->lbladdr);
+ }
+ }
+
+#endif
+
/* Second pass: translate the instructions */
machine->codeLen = 0;
+ /* Link label call push_byte which increments defaultCodePC.
+ We need to reset it so the compiled code goes in the
+ correct spot. */
+ machine->defaultCodePC = PROG_START;
if (!apply(asmlist, compileLine, machine))
return FALSE;
- if (machine->codeLen > 0 ){
- machine->memory[0x600+machine->codeLen] = 0x00;
+ if (machine->defaultCodePC > PROG_START ){
+ machine->memory[machine->defaultCodePC] = 0x00;
codeOk = TRUE;
}
else{
fprintf(stderr,"Invalid opcode!\n");
}
if( (machine->regPC == 0) ||
- (!machine->codeRunning) ||
- (machine->regPC > (machine->codeLen+0x600)) ) {
+ (!machine->codeRunning) ) {
machine->codeRunning = FALSE;
}
}
}
fprintf(output,"STACK:");
hexDump(machine,(STACK_TOP - stacksz) + 1, stacksz, output);
- fprintf(output,"\n================================================================================\n");
}
-
+void disassemble(machine_6502 *machine, FILE *output){
+ /* Read the opcode
+ increment the program counter
+ print the opcode
+ loop until end of program. */
+ AddrMode adm;
+ Bit16 addr;
+ Bit8 opcode;
+ int opidx;
+ char *mem;
+ int i;
+ Bit16 opc = machine->regPC;
+ mem = calloc(20,sizeof(char));
+ machine->regPC = PROG_START;
+ do{
+ addr = machine->regPC;
+ opcode = popByte(machine);
+ opidx = opIndex(machine,opcode,&adm);
+ for (i = 0; i < 20; i++) mem[i] = '\0';
+ dismem(machine, adm, mem);
+ fprintf(output,"%x\t%s\t%s\n",
+ addr,machine->opcodes[opidx].name,mem);
+ }while((machine->regPC - PROG_START) < machine->codeLen); /*XXX - may need to change since defaultCodePC */
+ free(mem);
+ machine->regPC = opc;
+}
\f
-void eval_file(machine_6502 *machine, char *filename, Plotter plot, void *plotterState){
+void eval_file(machine_6502 *machine, const char *filename, Plotter plot, void *plotterState){
char *code = NULL;
machine->plot = plot;
code = fileToBuffer(filename);
- if (! compileCode(machine, code) ){
- eprintf("Could not compile code.\n");
- }
+ if (! compileCode(machine, code) ) abort();
free(code);
- machine->regPC = 0x600;
+ machine->defaultCodePC = machine->regPC = PROG_START;
machine->codeRunning = TRUE;
do{
sleep(0); /* XXX */
trace(machine);
#endif
execute(machine);
- if (!machine->codeRunning)
- break;
- }while((machine->regPC - 0x600) < machine->codeLen);
+ }while(machine->codeRunning);
}
-void start_eval_file(machine_6502 *machine, char *filename, Plotter plot, void *plotterState){
+void start_eval_file(machine_6502 *machine, const char *filename, Plotter plot, void *plotterState){
char *code = NULL;
reset(machine);
code = fileToBuffer(filename);
- if (! compileCode(machine, code) ){
- eprintf("Could not compile code.\n");
- }
+ if (! compileCode(machine, code) ) abort();
free(code);
- machine->regPC = 0x600;
+ machine->defaultCodePC = machine->regPC = PROG_START;
machine->codeRunning = TRUE;
execute(machine);
}
-void start_eval_binary(machine_6502 *machine, Bit8 *program,
- unsigned int proglen,
+void start_eval_string(machine_6502 *machine, const char *code,
Plotter plot, void *plotterState){
- unsigned int pc, n;
reset(machine);
+
machine->plot = plot;
machine->plotterState = plotterState;
- machine->regPC = 0x600;
- pc = machine->regPC;
- machine->codeLen = proglen;
- n = 0;
- while (n < proglen){
- machine->memory[pc++] = program[n++];
+ if (! compileCode(machine, code) ){
+ fprintf(stderr,"Could not compile code.\n");
}
+
+ machine->defaultCodePC = machine->regPC = PROG_START;
machine->codeRunning = TRUE;
execute(machine);
}
+/* void start_eval_binary(machine_6502 *machine, Bit8 *program, */
+/* unsigned int proglen, */
+/* Plotter plot, void *plotterState){ */
+/* unsigned int pc, n; */
+/* reset(machine); */
+/* machine->plot = plot; */
+/* machine->plotterState = plotterState; */
+
+/* machine->regPC = PROG_START; */
+/* pc = machine->regPC; */
+/* machine->codeLen = proglen; */
+/* n = 0; */
+/* while (n < proglen){ */
+/* machine->memory[pc++] = program[n++]; */
+/* } */
+/* machine->codeRunning = TRUE; */
+/* execute(machine); */
+/* } */
+
void next_eval(machine_6502 *machine, int insno){
int i = 0;
for (i = 1; i < insno; i++){
- if (machine->codeRunning){/* && ((machine->regPC - 0x600) < machine->codeLen))*/
+ if (machine->codeRunning){
#if 0
- trace(machine);
+ trace(machine, stdout);
#endif
execute(machine);
}
projects / xscreensaver / blobdiff