Proof of concept of UXN on the GBA

6 files changed, 494 insertions, 0 deletions

diff --git a/src/uxn/devices/ppu.c b/src/uxn/devices/ppu.c
new file mode 100644
index 0000000..b977f97
--- /dev/null
+++ b/src/uxn/devices/ppu.c
@@ -0,0 +1,180 @@
+#include "ppu.h"
+
+/*
+Copyright (c) 2021 Devine Lu Linvega
+Copyright (c) 2021 Andrew Alderwick
+
+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.
+*/
+
+static Uint8 font[][8] = {
+        {0x00, 0x7c, 0x82, 0x82, 0x82, 0x82, 0x82, 0x7c},
+        {0x00, 0x30, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10},
+        {0x00, 0x7c, 0x82, 0x02, 0x7c, 0x80, 0x80, 0xfe},
+        {0x00, 0x7c, 0x82, 0x02, 0x1c, 0x02, 0x82, 0x7c},
+        {0x00, 0x0c, 0x14, 0x24, 0x44, 0x84, 0xfe, 0x04},
+        {0x00, 0xfe, 0x80, 0x80, 0x7c, 0x02, 0x82, 0x7c},
+        {0x00, 0x7c, 0x82, 0x80, 0xfc, 0x82, 0x82, 0x7c},
+        {0x00, 0x7c, 0x82, 0x02, 0x1e, 0x02, 0x02, 0x02},
+        {0x00, 0x7c, 0x82, 0x82, 0x7c, 0x82, 0x82, 0x7c},
+        {0x00, 0x7c, 0x82, 0x82, 0x7e, 0x02, 0x82, 0x7c},
+        {0x00, 0x7c, 0x82, 0x02, 0x7e, 0x82, 0x82, 0x7e},
+        {0x00, 0xfc, 0x82, 0x82, 0xfc, 0x82, 0x82, 0xfc},
+        {0x00, 0x7c, 0x82, 0x80, 0x80, 0x80, 0x82, 0x7c},
+        {0x00, 0xfc, 0x82, 0x82, 0x82, 0x82, 0x82, 0xfc},
+        {0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x82, 0x7c},
+        {0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x80, 0x80}};
+
+Uint8
+readpixel(Uint8 *sprite, Uint8 h, Uint8 v)
+{
+        Uint8 ch1 = ((sprite[v] >> h) & 0x1);
+        Uint8 ch2 = (((sprite[v + 8] >> h) & 0x1) << 1);
+        return ch1 + ch2;
+}
+
+void
+clear(Ppu *p)
+{
+        int i, sz = p->height * p->width, rows = sz / 4;
+        for(i = 0; i < sz; ++i)
+                p->output[i] = p->colors[0];
+        for(i = 0; i < rows; i++) {
+                p->fg[i] = 0;
+                p->bg[i] = 0;
+        }
+}
+
+void
+putcolors(Ppu *p, Uint8 *addr)
+{
+        int i;
+        for(i = 0; i < 4; ++i) {
+                Uint8
+                        r = (*(addr + i / 2) >> (!(i % 2) << 2)) & 0x0f,
+                        g = (*(addr + 2 + i / 2) >> (!(i % 2) << 2)) & 0x0f,
+                        b = (*(addr + 4 + i / 2) >> (!(i % 2) << 2)) & 0x0f;
+                p->colors[i] = rgb15(r,g,b);
+        }
+        // p->colors[0] = COLOR_BLUE;
+        // p->colors[1] = COLOR_WHITE;
+        // p->colors[2] = COLOR_RED;
+        // p->colors[3] = COLOR_CYAN;
+}
+
+void
+putpixel(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 color)
+{
+        Uint16 row = (y % 8) + ((x / 8 + y / 8 * p->hor) * 16), col = 7 - (x % 8);
+        if(x >= p->hor * 8 || y >= p->ver * 8 || row > (p->hor * p->ver * 16) - 8)
+                return;
+        if(color == 0 || color == 2)
+                layer[row] &= ~(1UL << col);
+        else
+                layer[row] |= 1UL << col;
+        if(color == 0 || color == 1)
+                layer[row + 8] &= ~(1UL << col);
+        else
+                layer[row + 8] |= 1UL << col;
+}
+
+void
+puticn(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)
+{
+        Uint16 v, h;
+        for(v = 0; v < 8; v++)
+                for(h = 0; h < 8; h++) {
+                        Uint8 ch1 = ((sprite[v] >> (7 - h)) & 0x1);
+                        if(ch1 == 1 || (color != 0x05 && color != 0x0a && color != 0x0f))
+                                putpixel(p,
+                                        layer,
+                                        x + (flipx ? 7 - h : h),
+                                        y + (flipy ? 7 - v : v),
+                                        ch1 ? color % 4 : color / 4);
+                }
+}
+
+void
+putchr(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)
+{
+        Uint16 v, h;
+        for(v = 0; v < 8; v++)
+                for(h = 0; h < 8; h++) {
+                        Uint8 ch1 = ((sprite[v] >> (7 - h)) & 0x1) * color;
+                        Uint8 ch2 = ((sprite[v + 8] >> (7 - h)) & 0x1) * color;
+                        putpixel(p,
+                                layer,
+                                x + (flipx ? 7 - h : h),
+                                y + (flipy ? 7 - v : v),
+                                (((ch1 + ch2 * 2) + color / 4) & 0x3));
+                }
+}
+
+/* output */
+
+void
+drawpixel(Ppu *p, Uint16 x, Uint16 y, Uint8 color)
+{
+        if(x >= p->pad && x <= p->width - p->pad - 1 && y >= p->pad && y <= p->height - p->pad - 1)
+                p->output[y * p->width + x] = p->colors[color];
+}
+
+void
+drawdebugger(Ppu *p, Uint8 *stack, Uint8 ptr)
+{
+        Uint8 i, x, y, b;
+        for(i = 0; i < 0x20; ++i) { /* memory */
+                x = ((i % 8) * 3 + 1) * 8, y = (i / 8 + 1) * 8, b = stack[i];
+                puticn(p, p->bg, x, y, font[(b >> 4) & 0xf], 1 + (ptr == i) * 0x7, 0, 0);
+                puticn(p, p->bg, x + 8, y, font[b & 0xf], 1 + (ptr == i) * 0x7, 0, 0);
+        }
+        for(x = 0; x < 0x20; ++x) {
+                drawpixel(p, x, p->height / 2, 2);
+                drawpixel(p, p->width - x, p->height / 2, 2);
+                drawpixel(p, p->width / 2, p->height - x, 2);
+                drawpixel(p, p->width / 2, x, 2);
+                drawpixel(p, p->width / 2 - 16 + x, p->height / 2, 2);
+                drawpixel(p, p->width / 2, p->height / 2 - 16 + x, 2);
+        }
+}
+
+void
+drawppu(Ppu *p)
+{
+        Uint16 x, y;
+        for(y = 0; y < p->ver; ++y)
+                for(x = 0; x < p->hor; ++x) {
+                        Uint8 v, h;
+                        Uint16 key = (y * p->hor + x) * 16;
+                        for(v = 0; v < 8; v++)
+                                for(h = 0; h < 8; h++) {
+                                        Uint8 color = readpixel(&p->fg[key], h, v);
+                                        if(color == 0)
+                                                color = readpixel(&p->bg[key], h, v);
+                                        drawpixel(p, x * 8 + p->pad + 7 - h, y * 8 + p->pad + v, color);
+                                }
+                }
+}
+
+int
+initppu(Ppu *p, Uint8 hor, Uint8 ver, Uint8 pad)
+{
+        p->hor = hor;
+        p->ver = ver;
+        p->pad = pad;
+        p->width = (8 * p->hor + p->pad * 2);
+        p->height = (8 * p->ver + p->pad * 2);
+        if(!(p->output = malloc(p->width * p->height * sizeof(Uint16))))
+                return 0;
+        if(!(p->bg = malloc(p->width * p->height * sizeof(Uint8) / 4)))
+                return 0;
+        if(!(p->fg = malloc(p->width * p->height * sizeof(Uint8) / 4)))
+                return 0;
+        clear(p);
+        return 1;
+}
diff --git a/src/uxn/devices/ppu.h b/src/uxn/devices/ppu.h
new file mode 100644
index 0000000..187d364
--- /dev/null
+++ b/src/uxn/devices/ppu.h
@@ -0,0 +1,36 @@
+#ifndef UXNGBA_PPU_H
+#define UXNGBA_PPU_H
+
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+Copyright (c) 2021 Devine Lu Linvega
+Copyright (c) 2021 Andrew Alderwick
+
+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.
+*/
+
+typedef unsigned char Uint8;
+typedef unsigned short Uint16;
+typedef unsigned int Uint32;
+
+typedef struct Ppu {
+        Uint8 *bg, *fg;
+        Uint16 hor, ver, pad, width, height;
+        Uint16 *output, colors[4];
+} Ppu;
+
+int initppu(Ppu *p, Uint8 hor, Uint8 ver, Uint8 pad);
+void putcolors(Ppu *p, Uint8 *addr);
+void putpixel(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 color);
+void puticn(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);
+void putchr(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);
+void drawppu(Ppu *p);
+void drawdebugger(Ppu *p, Uint8 *stack, Uint8 ptr);
+#endif // UXNGBA_PPU_H
diff --git a/src/uxn/roms/console.c b/src/uxn/roms/console.c
new file mode 100644
index 0000000..13d669a
--- /dev/null
+++ b/src/uxn/roms/console.c
@@ -0,0 +1,5 @@
+u16 uxn_rom[] = {
+    0x0121, 0x9411, 0x1801, 0x2117, 0x0100, 0x9438, 0xf401, 0x230d,
+    0x4800, 0x6c65, 0x6f6c, 0x5720, 0x726f, 0x646c, 0x6620, 0x6f72,
+    0x206d, 0x5855, 0x214e, 0x000d
+};
diff --git a/src/uxn/roms/dvd.c b/src/uxn/roms/dvd.c
new file mode 100644
index 0000000..2cccc84
--- /dev/null
+++ b/src/uxn/roms/dvd.c
@@ -0,0 +1,22 @@
+u16 uxn_rom[] = {
+    0x4c21, 0x01fd, 0x3708, 0x4c21, 0x01f3, 0x370a, 0xdc21, 0x01f2,
+    0x370c, 0x0121, 0x0133, 0x3720, 0x2201, 0x2136, 0x0200, 0x013b,
+    0x3100, 0x2401, 0x2136, 0x0200, 0x013b, 0x3102, 0x2101, 0x0121,
+    0x2eb2, 0x0100, 0x2120, 0xb201, 0x012e, 0x3000, 0x2201, 0x2136,
+    0x2000, 0x2839, 0x0001, 0x2130, 0x0000, 0x2128, 0x0000, 0x0128,
+    0x0d09, 0x0401, 0x0110, 0x0800, 0x0401, 0x0111, 0x3002, 0x2401,
+    0x2136, 0x1000, 0x2839, 0x0201, 0x2130, 0x0000, 0x2128, 0x0000,
+    0x0128, 0x0d09, 0x0501, 0x0110, 0x0800, 0x0501, 0x0111, 0x3000,
+    0x0021, 0x0101, 0x0100, 0x1004, 0x0001, 0x2108, 0xfeff, 0x383a,
+    0x0138, 0x3100, 0x0201, 0x2130, 0x0100, 0x0001, 0x0501, 0x0110,
+    0x0800, 0xff21, 0x3afe, 0x3838, 0x0201, 0x0131, 0x2121, 0xb201,
+    0x002e, 0x210f, 0xfd01, 0x2c01, 0x0137, 0x3002, 0x0201, 0x2130,
+    0x1000, 0x2638, 0x2a01, 0x0137, 0x3000, 0x0001, 0x2130, 0x2000,
+    0x2638, 0x2801, 0xcf37, 0x2e01, 0x0117, 0x362c, 0x0021, 0x3808,
+    0x2c01, 0x2537, 0x0021, 0x3808, 0xab25, 0xe401, 0x230d, 0x2523,
+    0x0021, 0x3808, 0xab25, 0xca01, 0x230d, 0x4323, 0x006c, 0x3f1f,
+    0x3838, 0x7838, 0x007f, 0xfefe, 0x777e, 0xe377, 0x00c3, 0x1f0f,
+    0x7b3b, 0xe777, 0x00c7, 0xfefc, 0x878f, 0x0e07, 0x7ffc, 0x0000,
+    0xff0f, 0x077f, 0x0300, 0x0001, 0xf0ff, 0xfff8, 0x8700, 0x0000,
+    0x7fff, 0xff7f, 0xf000, 0x0000, 0xfce0, 0x80fc, 0x0a00,
+};
diff --git a/src/uxn/uxn.c b/src/uxn/uxn.c
new file mode 100644
index 0000000..796a980
--- /dev/null
+++ b/src/uxn/uxn.c
@@ -0,0 +1,196 @@
+#include <stdio.h>
+#include "uxn.h"
+
+/*
+Copyright (u) 2021 Devine Lu Linvega
+
+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.
+*/
+
+#pragma mark - Operations
+
+/* clang-format off */
+void   push8(Stack *s, Uint8 a) { if (s->ptr == 0xff) { s->error = 2; return; } s->dat[s->ptr++] = a; }
+Uint8  pop8_keep(Stack *s) { if (s->kptr == 0) { s->error = 1; return 0; } return s->dat[--s->kptr]; }
+Uint8  pop8_nokeep(Stack *s) { if (s->ptr == 0) { s->error = 1; return 0; } return s->dat[--s->ptr]; }
+static Uint8 (*pop8)(Stack *s);
+void   mempoke8(Uint8 *m, Uint16 a, Uint8 b) { m[a] = b; }
+Uint8  mempeek8(Uint8 *m, Uint16 a) { return m[a]; }
+void   devpoke8(Device *d, Uint8 a, Uint8 b) { d->dat[a & 0xf] = b; d->talk(d, a & 0x0f, 1); }
+Uint8  devpeek8(Device *d, Uint8 a) { d->talk(d, a & 0x0f, 0); return d->dat[a & 0xf];  }
+void   push16(Stack *s, Uint16 a) { push8(s, a >> 8); push8(s, a); }
+Uint16 pop16(Stack *s) { return pop8(s) + (pop8(s) << 8); }
+void   mempoke16(Uint8 *m, Uint16 a, Uint16 b) { mempoke8(m, a, b >> 8); mempoke8(m, a + 1, b); }
+Uint16 mempeek16(Uint8 *m, Uint16 a) { return (mempeek8(m, a) << 8) + mempeek8(m, a + 1); }
+void   devpoke16(Device *d, Uint8 a, Uint16 b) { devpoke8(d, a, b >> 8); devpoke8(d, a + 1, b); }
+Uint16 devpeek16(Device *d, Uint16 a) { return (devpeek8(d, a) << 8) + devpeek8(d, a + 1); }
+/* Stack */
+void op_brk(Uxn *u) { u->ram.ptr = 0; }
+void op_nop(Uxn *u) { (void)u; }
+void op_lit(Uxn *u) { push8(u->src, mempeek8(u->ram.dat, u->ram.ptr++)); }
+void op_pop(Uxn *u) { pop8(u->src); }
+void op_dup(Uxn *u) { Uint8 a = pop8(u->src); push8(u->src, a); push8(u->src, a); }
+void op_swp(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, a); push8(u->src, b); }
+void op_ovr(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b); push8(u->src, a); push8(u->src, b); }
+void op_rot(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src), c = pop8(u->src); push8(u->src, b); push8(u->src, a); push8(u->src, c); }
+/* Logic */
+void op_equ(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b == a); }
+void op_neq(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b != a); }
+void op_gth(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b > a); }
+void op_lth(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b < a); }
+void op_jmp(Uxn *u) { Uint8 a = pop8(u->src); u->ram.ptr += (Sint8)a; }
+void op_jnz(Uxn *u) { Uint8 a = pop8(u->src); if (pop8(u->src)) u->ram.ptr += (Sint8)a; }
+void op_jsr(Uxn *u) { Uint8 a = pop8(u->src); push16(u->dst, u->ram.ptr); u->ram.ptr += (Sint8)a; }
+void op_sth(Uxn *u) { Uint8 a = pop8(u->src); push8(u->dst, a); }
+/* Memory */
+void op_pek(Uxn *u) { Uint8 a = pop8(u->src); push8(u->src, mempeek8(u->ram.dat, a)); }
+void op_pok(Uxn *u) { Uint8 a = pop8(u->src); Uint8 b = pop8(u->src); mempoke8(u->ram.dat, a, b); }
+void op_ldr(Uxn *u) { Uint8 a = pop8(u->src); push8(u->src, mempeek8(u->ram.dat, u->ram.ptr + (Sint8)a)); }
+void op_str(Uxn *u) { Uint8 a = pop8(u->src); Uint8 b = pop8(u->src); mempoke8(u->ram.dat, u->ram.ptr + (Sint8)a, b); }
+void op_lda(Uxn *u) { Uint16 a = pop16(u->src); push8(u->src, mempeek8(u->ram.dat, a)); }
+void op_sta(Uxn *u) { Uint16 a = pop16(u->src); Uint8 b = pop8(u->src); mempoke8(u->ram.dat, a, b); }
+void op_dei(Uxn *u) { Uint8 a = pop8(u->src); push8(u->src, devpeek8(&u->dev[a >> 4], a)); }
+void op_deo(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); devpoke8(&u->dev[a >> 4], a, b); }
+/* Arithmetic */
+void op_add(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b + a); }
+void op_sub(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b - a); }
+void op_mul(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b * a); }
+void op_div(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b / a); }
+void op_and(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b & a); }
+void op_ora(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b | a); }
+void op_eor(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b ^ a); }
+void op_sft(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b >> (a & 0x07) << ((a & 0x70) >> 4)); }
+/* Stack */
+void op_lit16(Uxn *u) { push16(u->src, mempeek16(u->ram.dat, u->ram.ptr++)); u->ram.ptr++; }
+void op_pop16(Uxn *u) { pop16(u->src); }
+void op_dup16(Uxn *u) { Uint16 a = pop16(u->src); push16(u->src, a); push16(u->src, a); }
+void op_swp16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, a); push16(u->src, b); }
+void op_ovr16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b); push16(u->src, a); push16(u->src, b); }
+void op_rot16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src), c = pop16(u->src); push16(u->src, b); push16(u->src, a); push16(u->src, c); }
+/* Logic(16-bits) */
+void op_equ16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b == a); }
+void op_neq16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b != a); }
+void op_gth16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b > a); }
+void op_lth16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b < a); }
+void op_jmp16(Uxn *u) { u->ram.ptr = pop16(u->src); }
+void op_jnz16(Uxn *u) { Uint16 a = pop16(u->src); if (pop8(u->src)) u->ram.ptr = a; }
+void op_jsr16(Uxn *u) { push16(u->dst, u->ram.ptr); u->ram.ptr = pop16(u->src); }
+void op_sth16(Uxn *u) { Uint16 a = pop16(u->src); push16(u->dst, a); }
+/* Memory(16-bits) */
+void op_pek16(Uxn *u) { Uint8 a = pop8(u->src); push16(u->src, mempeek16(u->ram.dat, a)); }
+void op_pok16(Uxn *u) { Uint8 a = pop8(u->src); Uint16 b = pop16(u->src); mempoke16(u->ram.dat, a, b); }
+void op_ldr16(Uxn *u) { Uint8 a = pop8(u->src); push16(u->src, mempeek16(u->ram.dat, u->ram.ptr + (Sint8)a)); }
+void op_str16(Uxn *u) { Uint8 a = pop8(u->src); Uint16 b = pop16(u->src); mempoke16(u->ram.dat, u->ram.ptr + (Sint8)a, b); }
+void op_lda16(Uxn *u) { Uint16 a = pop16(u->src); push16(u->src, mempeek16(u->ram.dat, a)); }
+void op_sta16(Uxn *u) { Uint16 a = pop16(u->src); Uint16 b = pop16(u->src); mempoke16(u->ram.dat, a, b); }
+void op_dei16(Uxn *u) { Uint8 a = pop8(u->src); push16(u->src, devpeek16(&u->dev[a >> 4], a)); }
+void op_deo16(Uxn *u) { Uint8 a = pop8(u->src); Uint16 b = pop16(u->src); devpoke16(&u->dev[a >> 4], a, b); }
+/* Arithmetic(16-bits) */
+void op_add16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b + a); }
+void op_sub16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b - a); }
+void op_mul16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b * a); }
+void op_div16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b / a); }
+void op_and16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b & a); }
+void op_ora16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b | a); }
+void op_eor16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b ^ a); }
+void op_sft16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b >> (a & 0x000f) << ((a & 0x00f0) >> 4)); }
+
+void (*ops[])(Uxn *u) = {
+        op_brk, op_lit, op_nop, op_pop, op_dup, op_swp, op_ovr, op_rot,
+        op_equ, op_neq, op_gth, op_lth, op_jmp, op_jnz, op_jsr, op_sth,
+        op_pek, op_pok, op_ldr, op_str, op_lda, op_sta, op_dei, op_deo,
+        op_add, op_sub, op_mul, op_div, op_and, op_ora, op_eor, op_sft,
+        /* 16-bit */
+        op_brk,   op_lit16, op_nop,   op_pop16, op_dup16, op_swp16, op_ovr16, op_rot16,
+        op_equ16, op_neq16, op_gth16, op_lth16, op_jmp16, op_jnz16, op_jsr16, op_sth16,
+        op_pek16, op_pok16, op_ldr16, op_str16, op_lda16, op_sta16, op_dei16, op_deo16,
+        op_add16, op_sub16, op_mul16, op_div16, op_and16, op_ora16, op_eor16, op_sft16
+};
+
+/* clang-format on */
+
+#pragma mark - Core
+
+int
+haltuxn(Uxn *u, char *name, int id)
+{
+        txt_printf("Halted: %s#%04x, at 0x%04x\n", name, id, u->ram.ptr);
+        u->ram.ptr = 0;
+        return 0;
+}
+
+void
+opcuxn(Uxn *u, Uint8 instr)
+{
+        Uint8 op = instr & 0x3f, freturn = instr & 0x40, fkeep = instr & 0x80;
+        u->src = freturn ? &u->rst : &u->wst;
+        u->dst = freturn ? &u->wst : &u->rst;
+        if(fkeep) {
+                pop8 = pop8_keep;
+                u->src->kptr = u->src->ptr;
+        } else {
+                pop8 = pop8_nokeep;
+        }
+        (*ops[op])(u);
+}
+
+int
+stepuxn(Uxn *u, Uint8 instr)
+{
+        opcuxn(u, instr);
+        if(u->wst.error)
+                return haltuxn(u, u->wst.error == 1 ? "Working-stack underflow" : "Working-stack overflow", instr);
+        if(u->rst.error)
+                return haltuxn(u, u->rst.error == 1 ? "Return-stack underflow" : "Return-stack overflow", instr);
+        return 1;
+}
+
+int
+evaluxn(Uxn *u, Uint16 vec)
+{
+        u->ram.ptr = vec;
+        u->wst.error = 0;
+        u->rst.error = 0;
+        while(u->ram.ptr)
+                if(!stepuxn(u, u->ram.dat[u->ram.ptr++]))
+                        return 0;
+        return 1;
+}
+
+int
+bootuxn(Uxn *u)
+{
+        size_t i;
+        char *cptr = (char *)u;
+        for(i = 0; i < sizeof(*u); i++)
+                cptr[i] = 0;
+        return 1;
+}
+
+int
+loaduxn(Uxn *u, char *filepath)
+{
+        FILE *f;
+        if(!(f = fopen(filepath, "rb")))
+                return haltuxn(u, "Missing input rom.", 0);
+        fread(u->ram.dat + PAGE_PROGRAM, sizeof(u->ram.dat) - PAGE_PROGRAM, 1, f);
+        txt_printf("Uxn loaded[%s].\n", filepath);
+        return 1;
+}
+
+Device *
+portuxn(Uxn *u, Uint8 id, char *name, void (*talkfn)(Device *d, Uint8 b0, Uint8 w))
+{
+        Device *d = &u->dev[id];
+        d->addr = id * 0x10;
+        d->u = u;
+        d->mem = u->ram.dat;
+        d->talk = talkfn;
+        txt_printf("Device added #%02x: %s, at 0x%04x \n", id, name, d->addr);
+        return d;
+}
diff --git a/src/uxn/uxn.h b/src/uxn/uxn.h
new file mode 100644
index 0000000..b2c90ac
--- /dev/null
+++ b/src/uxn/uxn.h
@@ -0,0 +1,55 @@
+#ifndef UXNGBA_UXN_H
+#define UXNGBA_UXN_H
+
+#include <stdio.h>
+
+/*
+Copyright (c) 2021 Devine Lu Linvega
+
+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.
+*/
+
+typedef unsigned char Uint8;
+typedef signed char Sint8;
+typedef unsigned short Uint16;
+typedef signed short Sint16;
+
+#define PAGE_PROGRAM 0x0100
+
+typedef struct {
+        Uint8 ptr, kptr, error;
+        Uint8 dat[256];
+} Stack;
+
+typedef struct {
+        Uint16 ptr;
+        Uint8 dat[KB(16)];
+} Memory;
+
+typedef struct Device {
+        struct Uxn *u;
+        Uint8 addr, dat[16], *mem;
+        void (*talk)(struct Device *d, Uint8, Uint8);
+} Device;
+
+typedef struct Uxn {
+        Stack wst, rst, *src, *dst;
+        Memory ram;
+        Device dev[16];
+} Uxn;
+
+struct Uxn;
+
+void mempoke16(Uint8 *m, Uint16 a, Uint16 b);
+Uint16 mempeek16(Uint8 *m, Uint16 a);
+
+int loaduxn(Uxn *c, char *filepath);
+int bootuxn(Uxn *c);
+int evaluxn(Uxn *u, Uint16 vec);
+Device *portuxn(Uxn *u, Uint8 id, char *name, void (*talkfn)(Device *, Uint8, Uint8));
+#endif // UXNGBA_UXN_H