134 lines
3.7 KiB
C
134 lines
3.7 KiB
C
/*
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* Equi platform reference implementation
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*
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* Created in 2022 by Luxferre, released into public domain
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*
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* See equi.md file for the specification and manual
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*
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* @license Unlicense <https://unlicense.org>
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* @author Luxferre
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*/
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/* Standard includes with size optimizations for TCC */
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#ifdef __TINYC__
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#include <tcclib.h>
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#else
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#include <stdlib.h>
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#include <stdio.h>
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#endif
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/*
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* Non-standard includes
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* To save space, we emulate necessary conio functions on non-6502 systems, not vice versa
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*/
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#ifdef __CC65__
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#include <conio.h>
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#else
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#define cgetc() (fgetc(stdin))
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#define cputc(c) (fputc(c, stdout))
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#endif
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/* Definitions section */
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#define EQUI_VER "0.0.1"
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#define ushort unsigned short /* basic 16-bit integer */
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#define uchar unsigned char /* basic 8-bit integer */
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#define WS sizeof(ushort) /* Equi word size in bytes */
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#define CLT_ENTRY_LEN 6u /* Amount of significant compiled word characters */
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#define CLT_ENTRY_SIZE (CLT_ENTRY_LEN + WS) /* Full size in bytes taken by one CLT entry */
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#define BS 8u /* Backspace character code */
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/* Configuration section (constants overridable at compile-time) */
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/* Main and return stack size in bytes */
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#ifndef STACK_SIZE
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#define STACK_SIZE 256u
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#endif
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/* Literal stack size in bytes */
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#ifndef LIT_STACK_SIZE
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#define LIT_STACK_SIZE 32u
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#endif
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/* Command buffer size in bytes */
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#ifndef GPD_AREA_SIZE
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#define GPD_AREA_SIZE 6400u
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#endif
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/* Command buffer size in bytes */
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#ifndef CMD_BUF_SIZE
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#define CMD_BUF_SIZE 15600u
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#endif
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/* Maximum amount of CLT entries */
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#ifndef CLT_ENTRIES_MAX
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#define CLT_ENTRIES_MAX 512u
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#endif
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/* Some necessary constants and offsets derived from the above values */
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#define STACK_SIZE_WORDS (STACK_SIZE / WS) /* Main and return stack size in words */
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/*
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* Structures that describe Equi machine RAM using the above configuration
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*/
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struct CLTEntry {
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uchar name[CLT_ENTRY_LEN]; /* compiled word name */
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ushort loc; /* compiled word location */
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};
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struct EquiRAM {
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ushort main_stack[STACK_SIZE_WORDS];
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ushort return_stack[STACK_SIZE_WORDS];
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uchar literal_stack[LIT_STACK_SIZE];
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ushort pc; /* program counter */
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ushort msp; /* main stack pointer */
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ushort rsp; /* return stack pointer */
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uchar lsp; /* literal stack pointer */
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ushort cbp; /* compilation buffer pointer */
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ushort cltp; /* compilation lookup table pointer */
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unsigned int II:1; /* instruction ignore mode */
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unsigned int CM:1; /* compilation mode */
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unsigned int IM:1; /* interpretation mode */
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ushort gpd_start;
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ushort cmd_start;
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ushort cmd_size;
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ushort ibp; /* input buffer pointer */
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struct CLTEntry clt[CLT_ENTRIES_MAX]; /* compilation lookup table */
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uchar gpd[GPD_AREA_SIZE];
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uchar cmdbuf[CMD_BUF_SIZE];
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};
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/* Before running the main code, instantiate the machine RAM */
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static struct EquiRAM ram;
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/* Also create an alternative view of the same RAM area for direct offset-based access */
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static uchar* flatram = (uchar *)&ram;
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int main(int argc, char* argv[]) {
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/* initialize the RAM in the most standard way */
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ram.gpd_start = (uchar *)&ram.gpd - (uchar *)&ram.main_stack;
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ram.cmd_start = (uchar *)&ram.cmdbuf - (uchar *)&ram.main_stack;
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ram.cmd_size = CMD_BUF_SIZE;
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ram.pc = ram.cmd_start; /* Start execution from the start of command buffer */
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ram.ibp = ram.cmd_start; /* Start input buffering from the start of command buffer */
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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",
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(uchar *)&ram.clt - (uchar *)&ram.main_stack,
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(uchar *)&ram.gpd - (uchar *)&ram.clt,
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ram.gpd_start,
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ram.cmd_start - ram.gpd_start,
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ram.cmd_start, ram.cmd_size);
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cputc('>');
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cgetc();
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return 0;
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}
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