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some skeleton for further codebase

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This commit is contained in:
Luxferre
2022-08-07 22:20:48 +03:00
parent 11a73d1c6e
commit 27d12a1131
2 changed files with 240 additions and 8 deletions
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equi.c
+238 -7
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@@ -27,21 +27,22 @@
#include <conio.h>
#else
#define cgetc() (fgetc(stdin))
#define cputc(c) (fputc(c, stdout))
#define cgetc() (getchar())
#define cputc(c) (putchar(c))
#endif
/* Definitions section */
#define EQUI_VER "0.0.1"
#define cerr(s) (fputs(s, stderr))
#define ushort unsigned short /* basic 16-bit integer */
#define uchar unsigned char /* basic 8-bit integer */
#define WS sizeof(ushort) /* Equi word size in bytes */
#define CLT_ENTRY_LEN 6u /* Amount of significant compiled word characters */
#define CLT_ENTRY_SIZE (CLT_ENTRY_LEN + WS) /* Full size in bytes taken by one CLT entry */
#define BS 8u /* Backspace character code */
#define CR 13u /* Character return code */
/* Configuration section (constants overridable at compile-time) */
@@ -110,13 +111,209 @@ static struct EquiRAM ram;
/* Also create an alternative view of the same RAM area for direct offset-based access */
static uchar* flatram = (uchar *)&ram;
/* Error reporting codes */
enum EquiErrors {
SUCCESS=0,
STACK_OVERFLOW,
STACK_UNDERFLOW,
DIV_BY_ZERO,
CLT_OVERFLOW,
CMD_OVERFLOW,
INVALID_INSTRUCTION,
PORT_IO_ERROR
};
/* Error reporting method */
void trapout(errcode) {
if(errcode > 0) {
fprintf(stderr, "Error %d at 0x%x (instruction %c): ", errcode, ram.pc, ram.cmdbuf[ram.pc]);
switch(errcode) {
case STACK_OVERFLOW:
cerr("Stack overflow");
break;
case STACK_UNDERFLOW:
cerr("Stack underflow");
break;
case DIV_BY_ZERO:
cerr("Division by zero");
break;
case CLT_OVERFLOW:
cerr("Compilation lookup table full");
break;
case CMD_OVERFLOW:
cerr("Command buffer full");
break;
case INVALID_INSTRUCTION:
cerr("Invalid instruction");
break;
case PORT_IO_ERROR:
cerr("Port I/O error");
break;
}
exit(errcode);
}
}
/* Equi instructions enum */
enum EquiInstructions {
INS_IISTART='(',
INS_IIEND=')',
INS_CMSTART=':',
INS_CMEND=';',
INS_LITINT='#',
INS_LITSTR='"',
INS_LITCALL='\'',
INS_RET='R',
INS_M2R=']', /* main -> return */
INS_R2M='[', /* return -> main */
INS_LOAD='L',
INS_STORE='S',
INS_STOREBYTE='W',
INS_DROP='!',
INS_DUP='$',
INS_SWAP='%',
INS_ROT='@',
INS_OVER='\\',
INS_JUMP='J',
INS_IF='I',
INS_EXPOINT='X', /* locate execution point */
INS_GT='>',
INS_LT='<',
INS_EQ='=',
INS_ADD='+',
INS_SUB='-',
INS_MUL='*',
INS_DIV='/',
INS_NEG='N',
INS_NOT='~',
INS_AND='&',
INS_OR='|',
INS_XOR='^',
INS_COUT='.',
INS_NBKIN=',', /* non-blocking key input */
INS_BKIN='?', /* blocking key input */
INS_PORTIO='P',
INS_PERSIST_WRITE='}',
INS_PERSIST_READ='{',
INS_QUIT='Q'
};
/* push a value onto the main stack */
void pushMain(ushort val) {
ram.main_stack[ram.msp++] = val;
if(ram.msp >= STACK_SIZE_WORDS)
trapout(STACK_OVERFLOW);
}
/* push a value onto the return stack */
void pushRet(ushort val) {
ram.return_stack[ram.rsp++] = val;
if(ram.rsp >= STACK_SIZE_WORDS)
trapout(STACK_OVERFLOW);
}
/* pop a value from the main stack */
ushort popMain() {
if(ram.msp == 0)
trapout(STACK_UNDERFLOW);
else
return ram.main_stack[--ram.msp];
}
/* pop a value from the return stack */
ushort popRet() {
if(ram.rsp == 0)
trapout(STACK_UNDERFLOW);
else
return ram.return_stack[--ram.rsp];
}
/* push a character to the literal stack, auto-discarding overflown items */
void pushLit(uchar c) {
ram.literal_stack[ram.lsp++] = c;
if(ram.lsp >= LIT_STACK_SIZE)
ram.lsp = 0;
}
/* pop a character from the literal stack */
uchar popLit() {
if(ram.lsp == 0)
trapout(STACK_UNDERFLOW);
else
return ram.literal_stack[--ram.lsp];
}
/* check literal stack and push 4 top values as hex short literal if not empty and discard the rest of the stack */
void attemptPushNumericLiteral() {
}
/* Main interpreter loop */
void equi_main_loop() {
uchar instr;
while(1) { /* iterate over the instructions in the command buffer */
instr = ram.cmdbuf[++ram.pc];
/* first, check for II mode */
if(ram.II) {
if(instr == ')')
ram.II = 0; /* unset instruction ignore mode flag */
continue;
}
/* then, check for compilation mode */
if(ram.CM) {
if(instr == ';') { /* trigger word compilation logic as per the spec */
ram.cmdbuf[ram.pc] = 'R'; /* in-place patch this instruction to R */
ram.clt[ram.cltp].loc = ram.cbp; /* stored the compiled code location from the most recent CBP value */
++ram.cltp; /* increase the word */
if(ram.cltp == CLT_ENTRIES_MAX) {
trapout(CLT_OVERFLOW);
break;
}
ram.CM = 0; /* unset compilation mode flag */
}
continue;
}
/* other than that, continue with interpretation mode */
/* first, detect lowercase, underscore, digit and A to F */
if((instr >= '0' && instr <= '9') || (instr >= 'A' && instr <= 'F') || instr == '_' || (instr >= 'a' && instr <= 'z')) {
pushLit(instr);
continue;
}
/* then trigger literal auto-push if applicable */
if(instr != '"' && instr != '\'' && instr != '#' && instr != ':')
attemptPushNumericLiteral();
switch(instr) {
default:
goto brx;
}
continue;
brx: break;
}
/* unset interpretation mode flag and exit */
ram.IM = 0;
}
/* Equi VM entry point */
int main(int argc, char* argv[]) {
/* _attempt_ to disable buffering for char input/output */
#ifndef __CC65__
setvbuf(stdin, NULL, _IONBF, 0);
setvbuf(stdout, NULL, _IONBF, 0);
#endif
uchar instr;
/* initialize the RAM in the most standard way */
ram.gpd_start = (uchar *)&ram.gpd - (uchar *)&ram.main_stack;
ram.cmd_start = (uchar *)&ram.cmdbuf - (uchar *)&ram.main_stack;
ram.cmd_size = CMD_BUF_SIZE;
ram.pc = ram.cmd_start; /* Start execution from the start of command buffer */
ram.ibp = ram.cmd_start; /* Start input buffering from the start of command buffer */
ram.II = ram.CM = ram.IM = 0; /* reset all flags */
/* Start both execution and input buffering from the start of command buffer (-1 because we use prefix increment) */
ram.pc = ram.ibp = ram.cmd_start-1;
printf("Welcome to Equi v" EQUI_VER " by Luxferre, 2022\n\nCLT: 0x%X (%d bytes)\nGPD: 0x%X (%d bytes)\nCommand buffer: 0x%X (%d bytes)\nEqui ready\n\n",
(uchar *)&ram.clt - (uchar *)&ram.main_stack,
@@ -126,8 +323,42 @@ int main(int argc, char* argv[]) {
ram.cmd_start, ram.cmd_size);
cputc('>');
cgetc();
cputc(' ');
while(1) { /* Now, we're in the command mode loop */
instr = ram.cmdbuf[++ram.ibp] = cgetc(); /* Fetch the next instruction from the keyboard */
if(instr == BS && ram.ibp > ram.cmd_start) { /* process the backspace */
#ifdef __CC65__
cputc(instr); /* echo it */
#endif
--ram.ibp;
} else if(instr == '(') { /* process II just to avoid quitting in command mode */
#ifdef __CC65__
cputc(instr); /* echo it */
#endif
ram.II = 1;
} else if(instr == ')') { /* process II just to avoid quitting in command mode */
#ifdef __CC65__
cputc(instr); /* echo it */
#endif
ram.II = 0;
} else if(instr == CR) { /* process carriage return */
cputc(CR); /* echo it */
#ifdef __CC65__
cputc(10); /* echo it */
#endif
ram.IM = 1; /* set the mandatory interpretation mode flag */
equi_main_loop(); /* and run the interpreter loop */
cputc(CR); /* echo it */
#ifdef __CC65__
cputc(10); /* echo it */
#endif
cputc('>');
cputc(' ');
}
#ifdef __CC65__
else cputc(instr); /* echo it */
#endif
} /* command mode loop end */
return 0;
}