mirror of https://git.sr.ht/~rabbits/uxn
124 lines
6.5 KiB
C
124 lines
6.5 KiB
C
#include "uxn.h"
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/*
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Copyright (u) 2022-2023 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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/* Registers
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[ Z ][ Y ][ X ][ L ][ N ][ T ] <
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[ . ][ . ][ . ][ H2 ][ . ] <
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[ L2 ][ N2 ][ T2 ] <
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*/
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#define T *(s->dat + s->ptr)
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#define N *(s->dat + (Uint8)(s->ptr - 1))
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#define L *(s->dat + (Uint8)(s->ptr - 2))
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#define X *(s->dat + (Uint8)(s->ptr - 3))
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#define Y *(s->dat + (Uint8)(s->ptr - 4))
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#define Z *(s->dat + (Uint8)(s->ptr - 5))
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#define T2 (N << 8 | T)
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#define H2 (L << 8 | N)
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#define N2 (X << 8 | L)
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#define L2 (Z << 8 | Y)
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#define T2_(v) { r = (v); T = r; N = r >> 8; }
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#define N2_(v) { r = (v); L = r; X = r >> 8; }
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#define L2_(v) { r = (v); Y = r; Z = r >> 8; }
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#define FLIP { s = ins & 0x40 ? &u->wst : &u->rst; }
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#define SHIFT(y) { s->ptr += (y); }
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#define SET(x, y) { SHIFT((ins & 0x80) ? x + y : y) }
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int
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uxn_eval(Uxn *u, Uint16 pc)
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{
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Uint16 t, n, l, r;
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Uint8 *ram = u->ram, *rr;
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if(!pc || u->dev[0x0f]) return 0;
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for(;;) {
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Uint8 ins = ram[pc++];
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Stack *s = ins & 0x40 ? &u->rst : &u->wst;
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switch(ins & 0x3f) {
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/* IMM */
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case 0x00: case 0x20:
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switch(ins) {
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case 0x00: /* BRK */ return 1;
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case 0x20: /* JCI */ t=T; SHIFT(-1) if(!t) { pc += 2; break; } /* fall-through */
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case 0x40: /* JMI */ rr = ram + pc; pc += 2 + PEEK2(rr); break;
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case 0x60: /* JSI */ SHIFT( 2) rr = ram + pc; pc += 2; T2_(pc); pc += PEEK2(rr); break;
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case 0x80: /* LIT */ case 0xc0: SHIFT( 1) T = ram[pc++]; break;
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case 0xa0: /* LIT2 */ case 0xe0: SHIFT( 2) N = ram[pc++]; T = ram[pc++]; break;
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} break;
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/* ALU */
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case 0x01: /* INC */ t=T; SET(1, 0) T = t + 1; break;
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case 0x21: /* INC2 */ t=T2; SET(2, 0) T2_(t + 1) break;
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case 0x02: /* POP */ SET(1,-1) break;
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case 0x22: /* POP2 */ SET(2,-2) break;
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case 0x03: /* NIP */ t=T; SET(2,-1) T = t; break;
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case 0x23: /* NIP2 */ t=T2; SET(4,-2) T2_(t) break;
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case 0x04: /* SWP */ t=T;n=N; SET(2, 0) T = n; N = t; break;
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case 0x24: /* SWP2 */ t=T2;n=N2; SET(4, 0) T2_(n) N2_(t) break;
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case 0x05: /* ROT */ t=T;n=N;l=L; SET(3, 0) T = l; N = t; L = n; break;
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case 0x25: /* ROT2 */ t=T2;n=N2;l=L2; SET(6, 0) T2_(l) N2_(t) L2_(n) break;
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case 0x06: /* DUP */ t=T; SET(1, 1) T = t; N = t; break;
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case 0x26: /* DUP2 */ t=T2; SET(2, 2) T2_(t) N2_(t) break;
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case 0x07: /* OVR */ t=T;n=N; SET(2, 1) T = n; N = t; L = n; break;
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case 0x27: /* OVR2 */ t=T2;n=N2; SET(4, 2) T2_(n) N2_(t) L2_(n) break;
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case 0x08: /* EQU */ t=T;n=N; SET(2,-1) T = n == t; break;
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case 0x28: /* EQU2 */ t=T2;n=N2; SET(4,-3) T = n == t; break;
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case 0x09: /* NEQ */ t=T;n=N; SET(2,-1) T = n != t; break;
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case 0x29: /* NEQ2 */ t=T2;n=N2; SET(4,-3) T = n != t; break;
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case 0x0a: /* GTH */ t=T;n=N; SET(2,-1) T = n > t; break;
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case 0x2a: /* GTH2 */ t=T2;n=N2; SET(4,-3) T = n > t; break;
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case 0x0b: /* LTH */ t=T;n=N; SET(2,-1) T = n < t; break;
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case 0x2b: /* LTH2 */ t=T2;n=N2; SET(4,-3) T = n < t; break;
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case 0x0c: /* JMP */ t=T; SET(1,-1) pc += (Sint8)t; break;
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case 0x2c: /* JMP2 */ t=T2; SET(2,-2) pc = t; break;
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case 0x0d: /* JCN */ t=T;n=N; SET(2,-2) if(n) pc += (Sint8)t; break;
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case 0x2d: /* JCN2 */ t=T2;n=L; SET(3,-3) if(n) pc = t; break;
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case 0x0e: /* JSR */ t=T; SET(1,-1) FLIP SHIFT(2) T2_(pc) pc += (Sint8)t; break;
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case 0x2e: /* JSR2 */ t=T2; SET(2,-2) FLIP SHIFT(2) T2_(pc) pc = t; break;
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case 0x0f: /* STH */ t=T; SET(1,-1) FLIP SHIFT(1) T = t; break;
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case 0x2f: /* STH2 */ t=T2; SET(2,-2) FLIP SHIFT(2) T2_(t) break;
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case 0x10: /* LDZ */ t=T; SET(1, 0) T = ram[t]; break;
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case 0x30: /* LDZ2 */ t=T; SET(1, 1) N = ram[t++]; T = ram[(Uint8)t]; break;
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case 0x11: /* STZ */ t=T;n=N; SET(2,-2) ram[t] = n; break;
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case 0x31: /* STZ2 */ t=T;n=H2; SET(3,-3) ram[t++] = n >> 8; ram[(Uint8)t] = n; break;
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case 0x12: /* LDR */ t=T; SET(1, 0) r = pc + (Sint8)t; T = ram[r]; break;
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case 0x32: /* LDR2 */ t=T; SET(1, 1) r = pc + (Sint8)t; N = ram[r++]; T = ram[r]; break;
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case 0x13: /* STR */ t=T;n=N; SET(2,-2) r = pc + (Sint8)t; ram[r] = n; break;
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case 0x33: /* STR2 */ t=T;n=H2; SET(3,-3) r = pc + (Sint8)t; ram[r++] = n >> 8; ram[r] = n; break;
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case 0x14: /* LDA */ t=T2; SET(2,-1) T = ram[t]; break;
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case 0x34: /* LDA2 */ t=T2; SET(2, 0) N = ram[t++]; T = ram[t]; break;
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case 0x15: /* STA */ t=T2;n=L; SET(3,-3) ram[t] = n; break;
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case 0x35: /* STA2 */ t=T2;n=N2; SET(4,-4) ram[t++] = n >> 8; ram[t] = n; break;
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case 0x16: /* DEI */ t=T; SET(1, 0) T = emu_dei(u, t); break;
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case 0x36: /* DEI2 */ t=T; SET(1, 1) N = emu_dei(u, t++); T = emu_dei(u, t); break;
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case 0x17: /* DEO */ t=T;n=N; SET(2,-2) emu_deo(u, t, n); break;
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case 0x37: /* DEO2 */ t=T;n=N;l=L; SET(3,-3) emu_deo(u, t++, l); emu_deo(u, t, n); break;
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case 0x18: /* ADD */ t=T;n=N; SET(2,-1) T = n + t; break;
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case 0x38: /* ADD2 */ t=T2;n=N2; SET(4,-2) T2_(n + t) break;
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case 0x19: /* SUB */ t=T;n=N; SET(2,-1) T = n - t; break;
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case 0x39: /* SUB2 */ t=T2;n=N2; SET(4,-2) T2_(n - t) break;
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case 0x1a: /* MUL */ t=T;n=N; SET(2,-1) T = n * t; break;
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case 0x3a: /* MUL2 */ t=T2;n=N2; SET(4,-2) T2_(n * t) break;
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case 0x1b: /* DIV */ t=T;n=N; SET(2,-1) T = t ? n / t : 0; break;
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case 0x3b: /* DIV2 */ t=T2;n=N2; SET(4,-2) T2_(t ? n / t : 0) break;
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case 0x1c: /* AND */ t=T;n=N; SET(2,-1) T = n & t; break;
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case 0x3c: /* AND2 */ t=T2;n=N2; SET(4,-2) T2_(n & t) break;
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case 0x1d: /* ORA */ t=T;n=N; SET(2,-1) T = n | t; break;
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case 0x3d: /* ORA2 */ t=T2;n=N2; SET(4,-2) T2_(n | t) break;
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case 0x1e: /* EOR */ t=T;n=N; SET(2,-1) T = n ^ t; break;
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case 0x3e: /* EOR2 */ t=T2;n=N2; SET(4,-2) T2_(n ^ t) break;
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case 0x1f: /* SFT */ t=T;n=N; SET(2,-1) T = n >> (t & 0xf) << (t >> 4); break;
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case 0x3f: /* SFT2 */ t=T;n=H2; SET(3,-1) T2_(n >> (t & 0xf) << (t >> 4)) break;
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}
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}
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}
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