From 1bba517f3716e166a0d52224f43c100b44b12289 Mon Sep 17 00:00:00 2001
From: Devine Lu Linvega <aliceffekt@gmail.com>
Date: Mon, 19 Feb 2024 10:35:28 -0800
Subject: [PATCH] (abc-disp) Added dispatch table implementation core

---
 etc/cores/uxn-abc-disp.c | 85 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 etc/cores/uxn-abc-disp.c

diff --git a/etc/cores/uxn-abc-disp.c b/etc/cores/uxn-abc-disp.c
new file mode 100644
index 0000000..e19502b
--- /dev/null
+++ b/etc/cores/uxn-abc-disp.c
@@ -0,0 +1,85 @@
+#include "uxn.h"
+
+/*
+Copyright (u) 2022-2023 Devine Lu Linvega, Andrew Alderwick, Andrew Richards
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE.
+*/
+
+#define FLIP     { s = ins & 0x40 ? &u->wst : &u->rst; }
+#define JUMP(x)  { if(m2) pc = (x); else pc += (Sint8)(x); }
+#define POP1(o)  { o = s->dat[--*sp]; }
+#define POP2(o)  { o = s->dat[--*sp] | (s->dat[--*sp] << 0x8); }
+#define POPx(o)  { if(m2) { POP2(o) } else POP1(o) }
+#define PUSH1(y) { s->dat[s->ptr++] = (y); }
+#define PUSH2(y) { tt = (y); s->dat[s->ptr++] = tt >> 0x8; s->dat[s->ptr++] = tt; }
+#define PUSHx(y) { if(m2) { PUSH2(y) } else PUSH1(y) }
+#define PEEK(o, x, r) { if(m2) { r = (x); o = ram[r++] << 8 | ram[r]; } else o = ram[(x)]; }
+#define POKE(x, y, r) { if(m2) { r = (x); ram[r++] = y >> 8; ram[r] = y; } else ram[(x)] = (y); }
+#define DEVR(o, p)    { if(m2) { o = (emu_dei(u, p) << 8) | emu_dei(u, p + 1); } else o = emu_dei(u, p); }
+#define DEVW(p, y)    { if(m2) { emu_deo(u, p, y >> 8); emu_deo(u, p + 1, y); } else emu_deo(u, p, y); }
+#define next { ins = ram[pc++]; \
+	m2 = ins & 0x20; \
+	s = ins & 0x40 ? &u->rst : &u->wst; \
+	if(ins & 0x80) kp = s->ptr, sp = &kp; else sp = &s->ptr; \
+	goto *lut[ins & 0x1f]; }
+
+int
+uxn_eval(Uxn *u, Uint16 pc)
+{
+	Uint8 t, kp, *sp, ins, m2, *ram = u->ram;
+	Uint16 tt, a, b, c;
+	Stack *s;
+	static void* lut[] = {
+		&&_imm, &&_inc, &&_pop, &&_nip, &&_swp, &&_rot, &&_dup, &&_ovr,
+		&&_equ, &&_neq, &&_gth, &&_lth, &&_jmp, &&_jcn, &&_jsr, &&_sth,
+		&&_ldz, &&_stz, &&_ldr, &&_str, &&_lda, &&_sta, &&_dei, &&_deo,
+		&&_add, &&_sub, &&_mul, &&_div, &&_and, &&_ora, &&_eor, &&_sft };
+	if(!pc || u->dev[0x0f]) return 0;
+	next
+	_imm: 
+		switch(ins) {
+			case 0x00: /* BRK */ return 1;
+			case 0x20: /* JCI */ POP1(b) if(!b) { pc += 2; break; }
+			case 0x40: /* JMI */ a = ram[pc++] << 8 | ram[pc++]; pc += a; break;
+			case 0x60: /* JSI */ PUSH2(pc + 2) a = ram[pc++] << 8 | ram[pc++]; pc += a; break;
+			case 0x80: case 0xc0: /* LIT  */ PUSH1(ram[pc++]) break;
+			case 0xa0: case 0xe0: /* LIT2 */ PUSH1(ram[pc++]) PUSH1(ram[pc++]) break;
+		} next
+	_inc: POPx(a) PUSHx(a + 1) next
+	_pop: POPx(a) next
+	_nip: POPx(a) POPx(b) PUSHx(a) next
+	_swp: POPx(a) POPx(b) PUSHx(a) PUSHx(b) next
+	_rot: POPx(a) POPx(b) POPx(c) PUSHx(b) PUSHx(a) PUSHx(c) next
+	_dup: POPx(a) PUSHx(a) PUSHx(a) next
+	_ovr: POPx(a) POPx(b) PUSHx(b) PUSHx(a) PUSHx(b) next
+	_equ: POPx(a) POPx(b) PUSH1(b == a) next
+	_neq: POPx(a) POPx(b) PUSH1(b != a) next
+	_gth: POPx(a) POPx(b) PUSH1(b > a) next
+	_lth: POPx(a) POPx(b) PUSH1(b < a) next
+	_jmp: POPx(a) JUMP(a) next
+	_jcn: POPx(a) POP1(b) if(b) JUMP(a) next
+	_jsr: POPx(a) FLIP PUSH2(pc) JUMP(a) next
+	_sth: POPx(a) FLIP PUSHx(a) next
+	_ldz: POP1(a) PEEK(b, a, t) PUSHx(b) next
+	_stz: POP1(a) POPx(b) POKE(a, b, t) next
+	_ldr: POP1(a) PEEK(b, pc + (Sint8)a, tt) PUSHx(b) next
+	_str: POP1(a) POPx(b) POKE(pc + (Sint8)a, b, tt) next
+	_lda: POP2(a) PEEK(b, a, tt) PUSHx(b) next
+	_sta: POP2(a) POPx(b) POKE(a, b, tt) next
+	_dei: POP1(a) DEVR(b, a) PUSHx(b) next
+	_deo: POP1(a) POPx(b) DEVW(a, b) next
+	_add: POPx(a) POPx(b) PUSHx(b + a) next
+	_sub: POPx(a) POPx(b) PUSHx(b - a) next
+	_mul: POPx(a) POPx(b) PUSHx(b * a) next
+	_div: POPx(a) POPx(b) PUSHx(a ? b / a : 0) next
+	_and: POPx(a) POPx(b) PUSHx(b & a) next
+	_ora: POPx(a) POPx(b) PUSHx(b | a) next
+	_eor: POPx(a) POPx(b) PUSHx(b ^ a) next
+	_sft: POP1(a) POPx(b) PUSHx(b >> (a & 0xf) << (a >> 4)) next
+}
\ No newline at end of file