From a3562ba93f058a5d37e571b6963e1d3c3b4b84f5 Mon Sep 17 00:00:00 2001
From: David Montero Crespo <davidmonterocrespo24@gmail.com>
Date: Fri, 5 Jun 2026 12:21:17 -0300
Subject: [PATCH] fix(chipbus): Galaksija display renders legible text (ASCII
 font8x8)

Galaksija stores ASCII codes in its 0x2800 video RAM (verified by snooping
the boot: it writes "@'READY" + ">_" prompt). The original CHRGEN ROM uses
a hardware-specific addressing that does not map char-code*8 to a glyph, so
rendering through it produced garbled output. Render the ASCII codes with
the public-domain IBM/VGA 8x8 font (font8x8 by Daniel Hepper / Marcel
Sondaar) instead -- legible green-on-black phosphor text. The boot screen
now reads "@'READY" with the ">_" input prompt, exactly like a real
Galaksija. Tests updated to check the bright-green channel.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 .../chipbus-galaksija-computer.test.ts        |   4 +-
 .../chipbus-galaksija-display.test.ts         |  17 +-
 .../fixtures/chipbus/galaksija-display.wasm   | Bin 23469 -> 22542 bytes
 .../sdk/examples/galaksija-display.c          | 258 ++++++------------
 4 files changed, 88 insertions(+), 191 deletions(-)

diff --git a/frontend/src/__tests__/chipbus-galaksija-computer.test.ts b/frontend/src/__tests__/chipbus-galaksija-computer.test.ts
index 8ac4fdf5..41616f86 100644
--- a/frontend/src/__tests__/chipbus-galaksija-computer.test.ts
+++ b/frontend/src/__tests__/chipbus-galaksija-computer.test.ts
@@ -77,9 +77,9 @@ describe.skipIf(!have)('chipbus Phase 3 — full Galaksija computer renders READ
 
     expect(fb, 'display produced a framebuffer').not.toBeNull();
     // "READY" lives at video offset 2 (0x2802) -> row 0, cols 2..6. Count lit
-    // pixels across those five character cells (x 16..55, y 0..7).
+    // pixels (bright-green G channel) across those five character cells.
     let litReady = 0;
-    for (let y = 0; y < 8; y++) for (let x = 16; x < 56; x++) if (fb![(y * 256 + x) * 4] === 0xff) litReady++;
+    for (let y = 0; y < 8; y++) for (let x = 16; x < 56; x++) if (fb![(y * 256 + x) * 4 + 1] > 0x80) litReady++;
     expect(litReady, 'the READY prompt is rendered on screen').toBeGreaterThan(20);
 
     z80.dispose(); rom.dispose(); ram.dispose(); inv.dispose(); disp.dispose();
diff --git a/frontend/src/__tests__/chipbus-galaksija-display.test.ts b/frontend/src/__tests__/chipbus-galaksija-display.test.ts
index 86833c24..563bca86 100644
--- a/frontend/src/__tests__/chipbus-galaksija-display.test.ts
+++ b/frontend/src/__tests__/chipbus-galaksija-display.test.ts
@@ -51,18 +51,15 @@ describe.skipIf(!have)('chipbus Phase 3 — Galaksija display renders a characte
     pm.triggerPinChange(WR, true); // rising edge -> latch + render
 
     expect(fb, 'framebuffer produced').not.toBeNull();
-    // Cell (col 2, row 0) spans x 16..23, y 0..7. Count lit (white) pixels there.
-    let lit = 0;
-    for (let y = 0; y < 8; y++) {
-      for (let x = 16; x < 24; x++) {
-        const o = (y * 256 + x) * 4;
-        if (fb![o] === 0xff) lit++;
-      }
-    }
-    expect(lit, 'the R glyph lit some pixels in its cell').toBeGreaterThan(3);
+    // A lit pixel is bright green (G channel high); background is dark green.
+    const lit = (x: number, y: number) => fb![(y * 256 + x) * 4 + 1] > 0x80;
+    // Cell (col 2, row 0) spans x 16..23, y 0..7. Count lit pixels there.
+    let litCount = 0;
+    for (let y = 0; y < 8; y++) for (let x = 16; x < 24; x++) if (lit(x, y)) litCount++;
+    expect(litCount, 'the R glyph lit some pixels in its cell').toBeGreaterThan(3);
     // A blank cell elsewhere (col 0) stays dark.
     let litBlank = 0;
-    for (let y = 0; y < 8; y++) for (let x = 0; x < 8; x++) if (fb![(y * 256 + x) * 4] === 0xff) litBlank++;
+    for (let y = 0; y < 8; y++) for (let x = 0; x < 8; x++) if (lit(x, y)) litBlank++;
     expect(litBlank, 'an unwritten cell stays blank').toBe(0);
 
     disp.dispose();
diff --git a/frontend/src/__tests__/fixtures/chipbus/galaksija-display.wasm b/frontend/src/__tests__/fixtures/chipbus/galaksija-display.wasm
index b30200657ae13bde57a899c288411bdd841b8c27..94b818438b70dc752664475c71e61889176a8bc3 100644
GIT binary patch
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diff --git a/test/test_custom_chips/sdk/examples/galaksija-display.c b/test/test_custom_chips/sdk/examples/galaksija-display.c
index 9855bebf..d538e3e9 100644
--- a/test/test_custom_chips/sdk/examples/galaksija-display.c
+++ b/test/test_custom_chips/sdk/examples/galaksija-display.c
@@ -1,202 +1,102 @@
 /*
- * galaksija-display — Galaksija (1983) 32x16 text video, rendered from its
- * memory-mapped video RAM. Phase 3 of the multi-chip bus track
- * (project/multichip-bus/). Public-domain character generator (CHRGEN) by the
- * Galaksija project. The chip is a passive BUS SNOOP: it watches WR + the
- * address + data bus and, on a write into the 0x2800-0x2BFF video region,
- * stores the character and renders that cell into its framebuffer using CHRGEN.
- * It never drives the bus. The framebuffer (256x128 = 32x16 chars of 8x8) is
- * blitted to the chip canvas by the host (vx_framebuffer_init / vx_buffer_write).
+ * galaksija-display - Galaksija (1983) 32x16 text video rendered from its
+ * memory-mapped video RAM (Phase 3, project/multichip-bus/). Passive BUS SNOOP:
+ * watches WR + address + data; on a write into 0x2800-0x2BFF it renders the
+ * character into a 256x128 framebuffer. Never drives the bus.
  *
- * CHRGEN: 256 chars x 8 rows, 1 byte per row, bit = 0 -> lit pixel (inverted).
+ * Galaksija stores ASCII codes in video RAM (the monitor writes READY as
+ * 0x52,0x45,...). Rendered with the public-domain IBM/VGA 8x8 font (font8x8 by
+ * Daniel Hepper / Marcel Sondaar) for legible text. font8x8: 1 byte/row, bit 0
+ * (LSB) = leftmost pixel, 1 = lit. Green-on-black phosphor look.
  */
 #include "velxio-chip.h"
 #include <stdint.h>
 #include <stdbool.h>
-
 #define COLS 32
 #define ROWS 16
-#define CW 8
-#define CH 8
-#define FB_W (COLS*CW)
-#define FB_H (ROWS*CH)
-
-static const uint8_t chrgen[2048] = {
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xaf,0xbf,0xaf,0xaf,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xdf,0xdf,0xdf,0xdf,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0x03,0xcf,0x83,0x87,0x83,0x03,0x03,0x87,0x7b,0xc7,0x03,0x7b,0xfb,0x7b,0x7b,0x87,
-    0x83,0x87,0x83,0x87,0x03,0x7b,0x7b,0x7b,0x7b,0x7b,0x03,0x87,0x87,0x03,0x87,0xff,
-    0xff,0xef,0xd7,0xb7,0xdf,0xff,0xe7,0xf8,0xdf,0xef,0xff,0xff,0xff,0xff,0xff,0xbf,
-    0x87,0xdf,0x87,0x87,0xbf,0x03,0x87,0x03,0x87,0x87,0xff,0xff,0xff,0xff,0xff,0x87,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,0xff,0xf1,0x1f,0x11,
-    0xfb,0xb7,0x77,0x7b,0x77,0xfb,0xfb,0x7b,0x7b,0xef,0x7f,0xbb,0xfb,0x33,0x7b,0x7b,
-    0x7b,0x7b,0x7b,0x7b,0xef,0x7b,0x7b,0x7b,0x7b,0x7b,0x7f,0x7b,0x7b,0x7f,0x7b,0xff,
-    0xff,0xef,0xd7,0xb7,0x07,0x73,0xdb,0xfb,0xef,0xdf,0xef,0xef,0xff,0xff,0xff,0xbf,
-    0x7b,0xcf,0x7b,0x7b,0x9f,0xfb,0x7b,0x7b,0x7b,0x7b,0xe7,0xe7,0xbf,0xff,0xf7,0x7b,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xbb,0x7b,0x77,0xfb,0x77,0xfb,0xfb,0xfb,0x7b,0xef,0x7f,0xdb,0xfb,0x33,0x7b,0x7b,
-    0x7b,0x7b,0x7b,0xfb,0xef,0x7b,0x7b,0x7b,0x7b,0x7b,0xbf,0xfb,0xfb,0xbf,0xfb,0xff,
-    0xff,0xef,0xd7,0xb7,0xdb,0x73,0xdb,0xfb,0xf7,0xbf,0xab,0xef,0xff,0xff,0xff,0xdf,
-    0x7b,0xdf,0x7f,0x7f,0xaf,0xfb,0xfb,0x7f,0x7b,0x7b,0xe7,0xe7,0xdf,0xff,0xef,0x7b,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xfb,0x7b,0x77,0xfb,0x77,0xfb,0xfb,0xfb,0x7b,0xef,0x7f,0xeb,0xfb,0x4b,0x7b,0x7b,
-    0x7b,0x7b,0x7b,0xfb,0xef,0x7b,0xb7,0x7b,0xb7,0x7b,0xdf,0xfb,0xfb,0xdf,0xfb,0xff,
-    0xff,0xef,0xff,0x03,0xdb,0xbf,0xeb,0xfb,0xf7,0xbf,0xc7,0xef,0xff,0xff,0xff,0xdf,
-    0x3b,0xdf,0x7f,0x7f,0xb7,0x83,0x83,0xbf,0x7b,0x7b,0xff,0xff,0xef,0x03,0xdf,0x7f,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xeb,0x7b,0x87,0xfb,0x77,0x83,0x83,0x1b,0x03,0xef,0x7f,0xf3,0xfb,0x4b,0x73,0x7b,
-    0x83,0x7b,0x83,0x87,0xef,0x7b,0xb7,0x7b,0xcf,0x07,0xef,0xfb,0xfb,0xef,0x87,0xff,
-    0xff,0xef,0xff,0xb7,0x87,0xdf,0xf7,0xfb,0xf7,0xbf,0x83,0x83,0xff,0x03,0xff,0xef,
-    0x5b,0xdf,0xbf,0x9f,0xbb,0x7f,0x7b,0xdf,0x87,0x7b,0xff,0xff,0xf7,0xff,0xbf,0x9f,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xfb,0x03,0x77,0xfb,0x77,0xfb,0xfb,0x7b,0x7b,0xef,0x7f,0xeb,0xfb,0x7b,0x6b,0x7b,
-    0xfb,0x7b,0xeb,0x7f,0xef,0x7b,0xb7,0x4b,0xcf,0x7f,0xf7,0xfb,0xfb,0xf7,0x7f,0xff,
-    0xff,0xef,0xff,0xb7,0x6f,0xef,0xeb,0xfb,0xf7,0xbf,0xc7,0xef,0xff,0xff,0xff,0xef,
-    0x6b,0xdf,0xc7,0x7f,0xbb,0x7f,0x7b,0xef,0x7b,0x07,0xff,0xff,0xef,0x03,0xdf,0xef,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xf1,0xf1,0xf1,0xf1,0x1f,0x1f,0x1f,0x1f,0x11,0x11,0x11,0x11,
-    0xab,0x7b,0x77,0xfb,0x77,0xfb,0xfb,0x7b,0x7b,0xef,0x7b,0xdb,0xfb,0x7b,0x5b,0x7b,
-    0xfb,0x5b,0xdb,0x7f,0xef,0x7b,0xcf,0x4b,0xb7,0x7f,0xfb,0xfb,0xfb,0xfb,0x7f,0xff,
-    0xff,0xef,0xff,0x03,0x6f,0xf7,0x5b,0xfa,0xf7,0xbf,0xab,0xef,0xe7,0xff,0xff,0xf7,
-    0x73,0xdf,0xfb,0x7f,0x03,0x7f,0x7b,0xf7,0x7b,0x7f,0xe7,0xe7,0xdf,0xff,0xef,0xef,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xfb,0x7b,0x77,0x7b,0x77,0xfb,0xfb,0x7b,0x7b,0xef,0x7b,0xbb,0xfb,0x7b,0x3b,0x7b,
-    0xfb,0xbb,0xbb,0x7b,0xef,0x7b,0xcf,0x33,0x7b,0x7b,0xfb,0x7b,0x7b,0xfb,0x7b,0xff,
-    0xff,0xff,0xff,0xb7,0x83,0x3b,0xbb,0xfb,0xef,0xdf,0xef,0xef,0xe7,0xff,0xe7,0xf7,
-    0x7b,0xdf,0xfb,0x7b,0xbf,0x7b,0x7b,0xf7,0x7b,0x7b,0xe7,0xe7,0xbf,0xff,0xf7,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,
-    0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,
-    0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,
-    0x03,0x7b,0x83,0x87,0x83,0x03,0xfb,0x07,0x7b,0xc7,0x87,0x7b,0x03,0x7b,0x7b,0x87,
-    0xfb,0x47,0x7b,0x87,0xef,0x87,0xcf,0x7b,0x7b,0x87,0x03,0x87,0x87,0x03,0x87,0x03,
-    0xff,0xef,0xff,0xb7,0xef,0x3b,0x47,0xf8,0xdf,0xef,0xff,0xff,0xef,0xff,0xe7,0xfb,
-    0x87,0x8f,0x03,0x87,0xbf,0x87,0x87,0xf7,0x87,0x87,0xff,0xef,0xff,0xff,0xff,0xef,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,
-    0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,
-    0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xf7,0xff,0xff,0xfb,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xf7,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,
-    0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,
-    0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,
-    0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,0x1f,
-    0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,0x11,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
-    0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
+#define FB_W (COLS*8)
+#define FB_H (ROWS*8)
+static const uint8_t font8x8[1024] = {
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x18,0x3c,0x3c,0x18,0x18,0x00,0x18,0x00,
+    0x36,0x36,0x00,0x00,0x00,0x00,0x00,0x00,0x36,0x36,0x7f,0x36,0x7f,0x36,0x36,0x00,
+    0x0c,0x3e,0x03,0x1e,0x30,0x1f,0x0c,0x00,0x00,0x63,0x33,0x18,0x0c,0x66,0x63,0x00,
+    0x1c,0x36,0x1c,0x6e,0x3b,0x33,0x6e,0x00,0x06,0x06,0x03,0x00,0x00,0x00,0x00,0x00,
+    0x18,0x0c,0x06,0x06,0x06,0x0c,0x18,0x00,0x06,0x0c,0x18,0x18,0x18,0x0c,0x06,0x00,
+    0x00,0x66,0x3c,0xff,0x3c,0x66,0x00,0x00,0x00,0x0c,0x0c,0x3f,0x0c,0x0c,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x0c,0x0c,0x06,0x00,0x00,0x00,0x3f,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x0c,0x0c,0x00,0x60,0x30,0x18,0x0c,0x06,0x03,0x01,0x00,
+    0x3e,0x63,0x73,0x7b,0x6f,0x67,0x3e,0x00,0x0c,0x0e,0x0c,0x0c,0x0c,0x0c,0x3f,0x00,
+    0x1e,0x33,0x30,0x1c,0x06,0x33,0x3f,0x00,0x1e,0x33,0x30,0x1c,0x30,0x33,0x1e,0x00,
+    0x38,0x3c,0x36,0x33,0x7f,0x30,0x78,0x00,0x3f,0x03,0x1f,0x30,0x30,0x33,0x1e,0x00,
+    0x1c,0x06,0x03,0x1f,0x33,0x33,0x1e,0x00,0x3f,0x33,0x30,0x18,0x0c,0x0c,0x0c,0x00,
+    0x1e,0x33,0x33,0x1e,0x33,0x33,0x1e,0x00,0x1e,0x33,0x33,0x3e,0x30,0x18,0x0e,0x00,
+    0x00,0x0c,0x0c,0x00,0x00,0x0c,0x0c,0x00,0x00,0x0c,0x0c,0x00,0x00,0x0c,0x0c,0x06,
+    0x18,0x0c,0x06,0x03,0x06,0x0c,0x18,0x00,0x00,0x00,0x3f,0x00,0x00,0x3f,0x00,0x00,
+    0x06,0x0c,0x18,0x30,0x18,0x0c,0x06,0x00,0x1e,0x33,0x30,0x18,0x0c,0x00,0x0c,0x00,
+    0x3e,0x63,0x7b,0x7b,0x7b,0x03,0x1e,0x00,0x0c,0x1e,0x33,0x33,0x3f,0x33,0x33,0x00,
+    0x3f,0x66,0x66,0x3e,0x66,0x66,0x3f,0x00,0x3c,0x66,0x03,0x03,0x03,0x66,0x3c,0x00,
+    0x1f,0x36,0x66,0x66,0x66,0x36,0x1f,0x00,0x7f,0x46,0x16,0x1e,0x16,0x46,0x7f,0x00,
+    0x7f,0x46,0x16,0x1e,0x16,0x06,0x0f,0x00,0x3c,0x66,0x03,0x03,0x73,0x66,0x7c,0x00,
+    0x33,0x33,0x33,0x3f,0x33,0x33,0x33,0x00,0x1e,0x0c,0x0c,0x0c,0x0c,0x0c,0x1e,0x00,
+    0x78,0x30,0x30,0x30,0x33,0x33,0x1e,0x00,0x67,0x66,0x36,0x1e,0x36,0x66,0x67,0x00,
+    0x0f,0x06,0x06,0x06,0x46,0x66,0x7f,0x00,0x63,0x77,0x7f,0x7f,0x6b,0x63,0x63,0x00,
+    0x63,0x67,0x6f,0x7b,0x73,0x63,0x63,0x00,0x1c,0x36,0x63,0x63,0x63,0x36,0x1c,0x00,
+    0x3f,0x66,0x66,0x3e,0x06,0x06,0x0f,0x00,0x1e,0x33,0x33,0x33,0x3b,0x1e,0x38,0x00,
+    0x3f,0x66,0x66,0x3e,0x36,0x66,0x67,0x00,0x1e,0x33,0x07,0x0e,0x38,0x33,0x1e,0x00,
+    0x3f,0x2d,0x0c,0x0c,0x0c,0x0c,0x1e,0x00,0x33,0x33,0x33,0x33,0x33,0x33,0x3f,0x00,
+    0x33,0x33,0x33,0x33,0x33,0x1e,0x0c,0x00,0x63,0x63,0x63,0x6b,0x7f,0x77,0x63,0x00,
+    0x63,0x63,0x36,0x1c,0x1c,0x36,0x63,0x00,0x33,0x33,0x33,0x1e,0x0c,0x0c,0x1e,0x00,
+    0x7f,0x63,0x31,0x18,0x4c,0x66,0x7f,0x00,0x1e,0x06,0x06,0x06,0x06,0x06,0x1e,0x00,
+    0x03,0x06,0x0c,0x18,0x30,0x60,0x40,0x00,0x1e,0x18,0x18,0x18,0x18,0x18,0x1e,0x00,
+    0x08,0x1c,0x36,0x63,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,
+    0x0c,0x0c,0x18,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x1e,0x30,0x3e,0x33,0x6e,0x00,
+    0x07,0x06,0x06,0x3e,0x66,0x66,0x3b,0x00,0x00,0x00,0x1e,0x33,0x03,0x33,0x1e,0x00,
+    0x38,0x30,0x30,0x3e,0x33,0x33,0x6e,0x00,0x00,0x00,0x1e,0x33,0x3f,0x03,0x1e,0x00,
+    0x1c,0x36,0x06,0x0f,0x06,0x06,0x0f,0x00,0x00,0x00,0x6e,0x33,0x33,0x3e,0x30,0x1f,
+    0x07,0x06,0x36,0x6e,0x66,0x66,0x67,0x00,0x0c,0x00,0x0e,0x0c,0x0c,0x0c,0x1e,0x00,
+    0x30,0x00,0x30,0x30,0x30,0x33,0x33,0x1e,0x07,0x06,0x66,0x36,0x1e,0x36,0x67,0x00,
+    0x0e,0x0c,0x0c,0x0c,0x0c,0x0c,0x1e,0x00,0x00,0x00,0x33,0x7f,0x7f,0x6b,0x63,0x00,
+    0x00,0x00,0x1f,0x33,0x33,0x33,0x33,0x00,0x00,0x00,0x1e,0x33,0x33,0x33,0x1e,0x00,
+    0x00,0x00,0x3b,0x66,0x66,0x3e,0x06,0x0f,0x00,0x00,0x6e,0x33,0x33,0x3e,0x30,0x78,
+    0x00,0x00,0x3b,0x6e,0x66,0x06,0x0f,0x00,0x00,0x00,0x3e,0x03,0x1e,0x30,0x1f,0x00,
+    0x08,0x0c,0x3e,0x0c,0x0c,0x2c,0x18,0x00,0x00,0x00,0x33,0x33,0x33,0x33,0x6e,0x00,
+    0x00,0x00,0x33,0x33,0x33,0x1e,0x0c,0x00,0x00,0x00,0x63,0x6b,0x7f,0x7f,0x36,0x00,
+    0x00,0x00,0x63,0x36,0x1c,0x36,0x63,0x00,0x00,0x00,0x33,0x33,0x33,0x3e,0x30,0x1f,
+    0x00,0x00,0x3f,0x19,0x0c,0x26,0x3f,0x00,0x38,0x0c,0x0c,0x07,0x0c,0x0c,0x38,0x00,
+    0x18,0x18,0x18,0x00,0x18,0x18,0x18,0x00,0x07,0x0c,0x0c,0x38,0x0c,0x0c,0x07,0x00,
+    0x6e,0x3b,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
 };
-
 typedef struct { vx_pin a[14]; vx_pin d[8]; vx_pin wr; int wr_last; vx_buffer fb; } chip_t;
 static chip_t G;
 static uint8_t fbpix[FB_W*FB_H*4];
-
 static uint16_t read_addr(void){ uint16_t v=0; for(int i=0;i<14;i++) if(vx_pin_read(G.a[i])) v|=(1u<<i); return v; }
 static uint8_t read_data(void){ uint8_t v=0; for(int i=0;i<8;i++) if(vx_pin_read(G.d[i])) v|=(1u<<i); return v; }
-
-static void put_px(int x,int y,uint8_t lit){
-  if(x<0||y<0||x>=FB_W||y>=FB_H) return;
-  int o=(y*FB_W+x)*4; uint8_t v=lit?0xFF:0x00;
-  fbpix[o]=v; fbpix[o+1]=v; fbpix[o+2]=v; fbpix[o+3]=0xFF;
-}
-static void render_cell(int col,int row,uint8_t ch){
-  for(int line=0; line<CH; line++){
-    uint8_t bits=chrgen[((int)ch*8 + line) & 2047];
-    for(int px=0; px<CW; px++){
-      uint8_t lit = ((bits>>(7-px))&1) ? 0 : 1; /* 0 bit = lit */
-      put_px(col*CW+px, row*CH+line, lit);
-    }
-  }
-  vx_buffer_write(G.fb, 0, fbpix, sizeof(fbpix));
-}
-
-static void on_wr(void* u, vx_pin p, int value){
-  (void)u;(void)p;
-  /* latch on WR rising edge (data + address valid through the write) */
-  if(G.wr_last==0 && value==1){
-    uint16_t addr=read_addr();
-    /* video region 0x2800-0x2BFF: A13=1,A12=0,A11=1,A10=0 */
-    if((addr & 0x3C00) == 0x2800){
-      uint16_t off = addr & 0x3FF;        /* 0..1023 */
-      int row=off/COLS, col=off%COLS;
-      if(row<ROWS) render_cell(col,row,read_data());
-    }
-  }
-  G.wr_last=value;
-}
-
+static void put_px(int x,int y,uint8_t lit){ if((unsigned)x<FB_W&&(unsigned)y<FB_H){ int o=(y*FB_W+x)*4; fbpix[o]=lit?0x33:0x00; fbpix[o+1]=lit?0xE0:0x12; fbpix[o+2]=lit?0x33:0x00; fbpix[o+3]=0xFF; } }
+static void render_cell(int col,int row,uint8_t ch){ uint8_t c=ch&0x7f; for(int line=0;line<8;line++){ uint8_t bits=font8x8[c*8+line]; for(int px=0;px<8;px++) put_px(col*8+px,row*8+line,(bits>>px)&1);} vx_buffer_write(G.fb,0,fbpix,sizeof(fbpix)); }
+static void on_wr(void* u, vx_pin p, int value){ (void)u;(void)p; if(G.wr_last==0&&value==1){ uint16_t a=read_addr(); if((a&0x3C00)==0x2800){ uint16_t off=a&0x3FF; int row=off/COLS,col=off%COLS; if(row<ROWS) render_cell(col,row,read_data()); } } G.wr_last=value; }
 void chip_setup(void){
   char name[4];
   for(int i=0;i<14;i++){ name[0]='A'; if(i<10){name[1]='0'+i;name[2]=0;} else {name[1]='1';name[2]='0'+(i-10);name[3]=0;} G.a[i]=vx_pin_register(name,VX_INPUT);}
   for(int i=0;i<8;i++){ name[0]='D';name[1]='0'+i;name[2]=0; G.d[i]=vx_pin_register(name,VX_INPUT);}
   G.wr=vx_pin_register("WR",VX_INPUT); G.wr_last=vx_pin_read(G.wr);
   uint32_t w,h; G.fb=vx_framebuffer_init(&w,&h);
-  for(int i=0;i<FB_W*FB_H;i++){ fbpix[i*4]=0;fbpix[i*4+1]=0;fbpix[i*4+2]=0;fbpix[i*4+3]=0xFF; }
+  for(int i=0;i<FB_W*FB_H;i++){ fbpix[i*4]=0;fbpix[i*4+1]=0x12;fbpix[i*4+2]=0;fbpix[i*4+3]=0xFF; }
   vx_buffer_write(G.fb,0,fbpix,sizeof(fbpix));
   vx_pin_watch(G.wr,VX_EDGE_BOTH,on_wr,0);
 }