138 lines
5.3 KiB
C
138 lines
5.3 KiB
C
#include "uxn.h"
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/*
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Copyright (u) 2022 Devine Lu Linvega, Andrew Alderwick, Andrew Richards
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Permission to use, copy, modify, and distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE.
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*/
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/* clang-format off */
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/* a,b,c: general use. bs: byte/short bool. src, dst: stack ptrs, swapped in return mode.
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pc: program counter. sp: ptr to src stack ptr. kptr: "keep" mode copy of src stack ptr.
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x,y: macro in params. d: macro in device. j,k,dev: macro temp variables. o: macro out param. */
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#define PUSH8(s, x) { if(s->ptr == 0xff) { errcode = 2; goto err; } s->dat[s->ptr++] = (x); }
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#define PUSH16(s, x) { if((j = s->ptr) >= 0xfe) { errcode = 2; goto err; } k = (x); s->dat[j] = k >> 8; s->dat[j + 1] = k; s->ptr = j + 2; }
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#define PUSH(s, x) { if(bs) { PUSH16(s, (x)) } else { PUSH8(s, (x)) } }
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#define POP8(o) { if(!(j = *sp)) { errcode = 0; goto err; } o = (Uint16)src->dat[--j]; *sp = j; }
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#define POP16(o) { if((j = *sp) <= 1) { errcode = 0; goto err; } o = src->dat[j - 1]; o += src->dat[j - 2] << 8; *sp = j - 2; }
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#define POP(o) { if(bs) { POP16(o) } else { POP8(o) } }
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#define POKE(x, y) { if(bs) { u->ram[(x)] = (y) >> 8; u->ram[(x) + 1] = (y); } else { u->ram[(x)] = y; } }
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#define PEEK16(o, x) { o = (u->ram[(x)] << 8) + u->ram[(x) + 1]; }
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#define PEEK(o, x) { if(bs) { PEEK16(o, x) } else { o = u->ram[(x)]; } }
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#define DEVR(o, d, x) { dev = (d); o = dev->dei(dev, (x) & 0x0f); if(bs) { o = (o << 8) + dev->dei(dev, ((x) + 1) & 0x0f); } }
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#define DEVW8(x, y) { dev->dat[(x) & 0xf] = y; dev->deo(dev, (x) & 0x0f); }
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#define DEVW(d, x, y) { dev = (d); if(bs) { DEVW8((x), (y) >> 8); DEVW8((x) + 1, (y)); } else { DEVW8((x), (y)) } }
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#define WARP(x) { if(bs) pc = (x); else pc += (Sint8)(x); }
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#define LIMIT 0x40000 /* around 3 ms */
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int
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uxn_eval(Uxn *u, Uint16 pc)
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{
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unsigned int a, b, c, j, k, bs, instr, errcode;
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unsigned int limit = LIMIT;
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Uint8 kptr, *sp;
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Stack *src, *dst;
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Device *dev;
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if(!pc || u->dev[0].dat[0xf]) return 0;
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while((instr = u->ram[pc++])) {
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if(!limit--) {
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if(!uxn_interrupt()) {
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errcode = 6;
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goto timeout;
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}
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limit = LIMIT;
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}
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/* Return Mode */
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if(instr & 0x40) {
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src = &u->rst; dst = &u->wst;
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} else {
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src = &u->wst; dst = &u->rst;
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}
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/* Keep Mode */
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if(instr & 0x80) {
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kptr = src->ptr;
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sp = &kptr;
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} else {
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sp = &src->ptr;
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}
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/* Short Mode */
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bs = instr & 0x20 ? 1 : 0;
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switch(instr & 0x1f) {
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/* Stack */
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case 0x00: /* LIT */ PEEK(a, pc) PUSH(src, a) pc += 1 + bs; break;
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case 0x01: /* INC */ POP(a) PUSH(src, a + 1) break;
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case 0x02: /* POP */ POP(a) break;
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case 0x03: /* NIP */ POP(a) POP(b) PUSH(src, a) break;
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case 0x04: /* SWP */ POP(a) POP(b) PUSH(src, a) PUSH(src, b) break;
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case 0x05: /* ROT */ POP(a) POP(b) POP(c) PUSH(src, b) PUSH(src, a) PUSH(src, c) break;
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case 0x06: /* DUP */ POP(a) PUSH(src, a) PUSH(src, a) break;
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case 0x07: /* OVR */ POP(a) POP(b) PUSH(src, b) PUSH(src, a) PUSH(src, b) break;
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/* Logic */
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case 0x08: /* EQU */ POP(a) POP(b) PUSH8(src, b == a) break;
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case 0x09: /* NEQ */ POP(a) POP(b) PUSH8(src, b != a) break;
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case 0x0a: /* GTH */ POP(a) POP(b) PUSH8(src, b > a) break;
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case 0x0b: /* LTH */ POP(a) POP(b) PUSH8(src, b < a) break;
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case 0x0c: /* JMP */ POP(a) WARP(a) break;
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case 0x0d: /* JCN */ POP(a) POP8(b) if(b) WARP(a) break;
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case 0x0e: /* JSR */ POP(a) PUSH16(dst, pc) WARP(a) break;
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case 0x0f: /* STH */ POP(a) PUSH(dst, a) break;
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/* Memory */
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case 0x10: /* LDZ */ POP8(a) PEEK(b, a) PUSH(src, b) break;
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case 0x11: /* STZ */ POP8(a) POP(b) POKE(a, b) break;
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case 0x12: /* LDR */ POP8(a) PEEK(b, pc + (Sint8)a) PUSH(src, b) break;
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case 0x13: /* STR */ POP8(a) POP(b) c = pc + (Sint8)a; POKE(c, b) break;
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case 0x14: /* LDA */ POP16(a) PEEK(b, a) PUSH(src, b) break;
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case 0x15: /* STA */ POP16(a) POP(b) POKE(a, b) break;
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case 0x16: /* DEI */ POP8(a) DEVR(b, &u->dev[a >> 4], a) PUSH(src, b) break;
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case 0x17: /* DEO */ POP8(a) POP(b) DEVW(&u->dev[a >> 4], a, b) break;
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/* Arithmetic */
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case 0x18: /* ADD */ POP(a) POP(b) PUSH(src, b + a) break;
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case 0x19: /* SUB */ POP(a) POP(b) PUSH(src, b - a) break;
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case 0x1a: /* MUL */ POP(a) POP(b) PUSH(src, (Uint32)b * a) break;
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case 0x1b: /* DIV */ POP(a) POP(b) if(a == 0) { errcode = 4; goto err; } PUSH(src, b / a) break;
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case 0x1c: /* AND */ POP(a) POP(b) PUSH(src, b & a) break;
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case 0x1d: /* ORA */ POP(a) POP(b) PUSH(src, b | a) break;
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case 0x1e: /* EOR */ POP(a) POP(b) PUSH(src, b ^ a) break;
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case 0x1f: /* SFT */ POP8(a) POP(b) c = b >> (a & 0x0f) << ((a & 0xf0) >> 4); PUSH(src, c) break;
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}
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}
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return 1;
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err:
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/* set 1 in errcode if it involved the return stack instead of the working stack */
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/* (stack overflow & ( opcode was STH / JSR )) ^ Return Mode */
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errcode |= ((errcode >> 1 & ((instr & 0x1e) == 0x0e)) ^ instr >> 6) & 1;
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timeout:
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return uxn_halt(u, errcode, pc - 1);
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}
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/* clang-format on */
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int
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uxn_boot(Uxn *u, Uint8 *ram)
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{
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Uint32 i;
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char *cptr = (char *)u;
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for(i = 0; i < sizeof(*u); i++)
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cptr[i] = 0x00;
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u->ram = ram;
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return 1;
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}
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Device *
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uxn_port(Uxn *u, Uint8 id, Uint8 (*deifn)(Device *d, Uint8 port), void (*deofn)(Device *d, Uint8 port))
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{
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Device *d = &u->dev[id];
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d->u = u;
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d->dei = deifn;
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d->deo = deofn;
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return d;
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}
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