uxn

Varvara Ordinator, written in ANSI C(SDL2)
git clone https://git.eamoncaddigan.net/uxn.git
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uxn.c (6614B)


      1 #include "uxn.h"
      2 
      3 /*
      4 Copyright (u) 2022-2023 Devine Lu Linvega, Andrew Alderwick, Andrew Richards
      5 
      6 Permission to use, copy, modify, and distribute this software for any
      7 purpose with or without fee is hereby granted, provided that the above
      8 copyright notice and this permission notice appear in all copies.
      9 
     10 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     11 WITH REGARD TO THIS SOFTWARE.
     12 */
     13 
     14 /* Registers
     15 [ Z ][ Y ][ X ][ L ][ N ][ T ] <
     16 [ . ][ . ][ . ][   H2   ][ . ] <
     17 [   L2   ][   N2   ][   T2   ] <
     18 */
     19 
     20 #define T *(s->dat + s->ptr)
     21 #define N *(s->dat + (Uint8)(s->ptr - 1))
     22 #define L *(s->dat + (Uint8)(s->ptr - 2))
     23 #define X *(s->dat + (Uint8)(s->ptr - 3))
     24 #define Y *(s->dat + (Uint8)(s->ptr - 4))
     25 #define Z *(s->dat + (Uint8)(s->ptr - 5))
     26 #define T2 (N << 8 | T)
     27 #define H2 (L << 8 | N)
     28 #define N2 (X << 8 | L)
     29 #define L2 (Z << 8 | Y)
     30 #define T2_(v) { r = (v); T = r; N = r >> 8; }
     31 #define N2_(v) { r = (v); L = r; X = r >> 8; }
     32 #define L2_(v) { r = (v); Y = r; Z = r >> 8; }
     33 #define FLIP      { s = ins & 0x40 ? &u->wst : &u->rst; }
     34 #define SHIFT(y)  { s->ptr += (y); }
     35 #define SET(x, y) { SHIFT((ins & 0x80) ? x + y : y) }
     36 
     37 int
     38 uxn_eval(Uxn *u, Uint16 pc)
     39 {
     40 	Uint16 t, n, l, r;
     41 	Uint8 *ram = u->ram, *rr;
     42 	if(!pc || u->dev[0x0f]) return 0;
     43 	for(;;) {
     44 		Uint8 ins = ram[pc++];
     45 		Stack *s = ins & 0x40 ? &u->rst : &u->wst;
     46 		switch(ins & 0x3f) {
     47 		/* IMM */
     48 		case 0x00: case 0x20:
     49 			switch(ins) {
     50 			case 0x00: /* BRK  */                       return 1;
     51 			case 0x20: /* JCI  */ t=T;        SHIFT(-1) if(!t) { pc += 2; break; } /* fall-through */
     52 			case 0x40: /* JMI  */                       rr = ram + pc; pc += 2 + PEEK2(rr); break;
     53 			case 0x60: /* JSI  */             SHIFT( 2) rr = ram + pc; pc += 2; T2_(pc); pc += PEEK2(rr); break;
     54 			case 0x80: /* LIT  */ case 0xc0:  SHIFT( 1) T = ram[pc++]; break;
     55 			case 0xa0: /* LIT2 */ case 0xe0:  SHIFT( 2) N = ram[pc++]; T = ram[pc++]; break;
     56 			} break;
     57 		/* ALU */
     58 		case 0x01: /* INC  */ t=T;            SET(1, 0) T = t + 1; break;
     59 		case 0x21: /* INC2 */ t=T2;           SET(2, 0) T2_(t + 1) break;
     60 		case 0x02: /* POP  */                 SET(1,-1) break;
     61 		case 0x22: /* POP2 */                 SET(2,-2) break;
     62 		case 0x03: /* NIP  */ t=T;            SET(2,-1) T = t; break;
     63 		case 0x23: /* NIP2 */ t=T2;           SET(4,-2) T2_(t) break;
     64 		case 0x04: /* SWP  */ t=T;n=N;        SET(2, 0) T = n; N = t; break;
     65 		case 0x24: /* SWP2 */ t=T2;n=N2;      SET(4, 0) T2_(n) N2_(t) break;
     66 		case 0x05: /* ROT  */ t=T;n=N;l=L;    SET(3, 0) T = l; N = t; L = n; break;
     67 		case 0x25: /* ROT2 */ t=T2;n=N2;l=L2; SET(6, 0) T2_(l) N2_(t) L2_(n) break;
     68 		case 0x06: /* DUP  */ t=T;            SET(1, 1) T = t; N = t; break;
     69 		case 0x26: /* DUP2 */ t=T2;           SET(2, 2) T2_(t) N2_(t) break;
     70 		case 0x07: /* OVR  */ t=T;n=N;        SET(2, 1) T = n; N = t; L = n; break;
     71 		case 0x27: /* OVR2 */ t=T2;n=N2;      SET(4, 2) T2_(n) N2_(t) L2_(n) break;
     72 		case 0x08: /* EQU  */ t=T;n=N;        SET(2,-1) T = n == t; break;
     73 		case 0x28: /* EQU2 */ t=T2;n=N2;      SET(4,-3) T = n == t; break;
     74 		case 0x09: /* NEQ  */ t=T;n=N;        SET(2,-1) T = n != t; break;
     75 		case 0x29: /* NEQ2 */ t=T2;n=N2;      SET(4,-3) T = n != t; break;
     76 		case 0x0a: /* GTH  */ t=T;n=N;        SET(2,-1) T = n > t; break;
     77 		case 0x2a: /* GTH2 */ t=T2;n=N2;      SET(4,-3) T = n > t; break;
     78 		case 0x0b: /* LTH  */ t=T;n=N;        SET(2,-1) T = n < t; break;
     79 		case 0x2b: /* LTH2 */ t=T2;n=N2;      SET(4,-3) T = n < t; break;
     80 		case 0x0c: /* JMP  */ t=T;            SET(1,-1) pc += (Sint8)t; break;
     81 		case 0x2c: /* JMP2 */ t=T2;           SET(2,-2) pc = t; break;
     82 		case 0x0d: /* JCN  */ t=T;n=N;        SET(2,-2) if(n) pc += (Sint8)t; break;
     83 		case 0x2d: /* JCN2 */ t=T2;n=L;       SET(3,-3) if(n) pc = t; break;
     84 		case 0x0e: /* JSR  */ t=T;            SET(1,-1) FLIP SHIFT(2) T2_(pc) pc += (Sint8)t; break;
     85 		case 0x2e: /* JSR2 */ t=T2;           SET(2,-2) FLIP SHIFT(2) T2_(pc) pc = t; break;
     86 		case 0x0f: /* STH  */ t=T;            SET(1,-1) FLIP SHIFT(1) T = t; break;
     87 		case 0x2f: /* STH2 */ t=T2;           SET(2,-2) FLIP SHIFT(2) T2_(t) break;
     88 		case 0x10: /* LDZ  */ t=T;            SET(1, 0) T = ram[t]; break;
     89 		case 0x30: /* LDZ2 */ t=T;            SET(1, 1) N = ram[t++]; T = ram[(Uint8)t]; break;
     90 		case 0x11: /* STZ  */ t=T;n=N;        SET(2,-2) ram[t] = n; break;
     91 		case 0x31: /* STZ2 */ t=T;n=H2;       SET(3,-3) ram[t++] = n >> 8; ram[(Uint8)t] = n; break;
     92 		case 0x12: /* LDR  */ t=T;            SET(1, 0) r = pc + (Sint8)t; T = ram[r]; break;
     93 		case 0x32: /* LDR2 */ t=T;            SET(1, 1) r = pc + (Sint8)t; N = ram[r++]; T = ram[r]; break;
     94 		case 0x13: /* STR  */ t=T;n=N;        SET(2,-2) r = pc + (Sint8)t; ram[r] = n; break;
     95 		case 0x33: /* STR2 */ t=T;n=H2;       SET(3,-3) r = pc + (Sint8)t; ram[r++] = n >> 8; ram[r] = n; break;
     96 		case 0x14: /* LDA  */ t=T2;           SET(2,-1) T = ram[t]; break;
     97 		case 0x34: /* LDA2 */ t=T2;           SET(2, 0) N = ram[t++]; T = ram[t]; break;
     98 		case 0x15: /* STA  */ t=T2;n=L;       SET(3,-3) ram[t] = n; break;
     99 		case 0x35: /* STA2 */ t=T2;n=N2;      SET(4,-4) ram[t++] = n >> 8; ram[t] = n; break;
    100 		case 0x16: /* DEI  */ t=T;            SET(1, 0) T = emu_dei(u, t); break;
    101 		case 0x36: /* DEI2 */ t=T;            SET(1, 1) N = emu_dei(u, t++); T = emu_dei(u, t); break;
    102 		case 0x17: /* DEO  */ t=T;n=N;        SET(2,-2) emu_deo(u, t, n); break;
    103 		case 0x37: /* DEO2 */ t=T;n=N;l=L;    SET(3,-3) emu_deo(u, t++, l); emu_deo(u, t, n); break;
    104 		case 0x18: /* ADD  */ t=T;n=N;        SET(2,-1) T = n + t; break;
    105 		case 0x38: /* ADD2 */ t=T2;n=N2;      SET(4,-2) T2_(n + t) break;
    106 		case 0x19: /* SUB  */ t=T;n=N;        SET(2,-1) T = n - t; break;
    107 		case 0x39: /* SUB2 */ t=T2;n=N2;      SET(4,-2) T2_(n - t) break;
    108 		case 0x1a: /* MUL  */ t=T;n=N;        SET(2,-1) T = n * t; break;
    109 		case 0x3a: /* MUL2 */ t=T2;n=N2;      SET(4,-2) T2_(n * t) break;
    110 		case 0x1b: /* DIV  */ t=T;n=N;        SET(2,-1) T = t ? n / t : 0; break;
    111 		case 0x3b: /* DIV2 */ t=T2;n=N2;      SET(4,-2) T2_(t ? n / t : 0) break;
    112 		case 0x1c: /* AND  */ t=T;n=N;        SET(2,-1) T = n & t; break;
    113 		case 0x3c: /* AND2 */ t=T2;n=N2;      SET(4,-2) T2_(n & t) break;
    114 		case 0x1d: /* ORA  */ t=T;n=N;        SET(2,-1) T = n | t; break;
    115 		case 0x3d: /* ORA2 */ t=T2;n=N2;      SET(4,-2) T2_(n | t) break;
    116 		case 0x1e: /* EOR  */ t=T;n=N;        SET(2,-1) T = n ^ t; break;
    117 		case 0x3e: /* EOR2 */ t=T2;n=N2;      SET(4,-2) T2_(n ^ t) break;
    118 		case 0x1f: /* SFT  */ t=T;n=N;        SET(2,-1) T = n >> (t & 0xf) << (t >> 4); break;
    119 		case 0x3f: /* SFT2 */ t=T;n=H2;       SET(3,-1) T2_(n >> (t & 0xf) << (t >> 4)) break;
    120 		}
    121 	}
    122 }
    123