libc: add Sprinter palette API (graphics + text planes)

palette.h/video/palette.c wrap BIOS $A4 PIC_SET_PAL/PIC_GET_PAL and $A6 SET_PAL_INIT for the 8 palette pages (0-3 graphics, 4-7 text planes). gfx_palette.c and conio/text_palette.c are thin per-domain wrappers; text_palette.c maps the text "plane" 0..3 (paper/ink/blink-paper/ blink-ink) onto BIOS pages 4..7. Covered by tests/text_palette. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-06-23 17:07:55 +03:00
parent 5e5e70d0c8
commit 49a87b4d02
6 changed files with 501 additions and 0 deletions
@@ -0,0 +1,74 @@
+/*
+ * gfx_palette.c — graphics-side palette wrappers.
+ *
+ * The "legacy" entry points (gfx_pal_load / gfx_pal_set) keep their own
+ * inline-asm implementation rather than thunking through pal_*; this
+ * avoids depending on SDCC's __sdcccall(1) stack-shuffling for nested
+ * calls, which empirically misbehaves here (the trampoline corrupts the
+ * text palette so the next text-mode print hangs). Functionally these
+ * are identical to the old gfx_core.c versions.
+ *
+ * The newer get / reset helpers are simple wrappers — they're either
+ * not on hot paths or are first introduced here, so the thunk overhead
+ * doesn't matter and we get to share the asm with libc/video/palette.c.
+ */
+
+#include <stdint.h>
+#include <gfx.h>
+#include <palette.h>
+
+static uint8_t  gpl_num_;
+static uint8_t  gpl_start_;
+static uint8_t  gpl_count_;
+static uint16_t gpl_data_;
+
+void gfx_pal_load(uint8_t pal_num, uint8_t start, uint8_t count,
+                  const uint8_t *data)
+{
+    gpl_num_   = pal_num;
+    gpl_start_ = start;
+    gpl_count_ = count;
+    gpl_data_  = (uint16_t)(uintptr_t)data;
+
+    __asm
+        push  ix
+        ld    a, (_gpl_start_)
+        ld    e, a                  ; E = start
+        ld    a, (_gpl_count_)
+        ld    d, a                  ; D = count (0 → 256)
+        ld    hl, (_gpl_data_)      ; HL = data
+        ld    b, #0xFF              ; mask
+        ld    a, (_gpl_num_)        ; A = palette number
+        ld    c, #0xA4              ; BIOS PIC_SET_PAL
+        rst   #0x08
+        pop   ix
+    __endasm;
+}
+
+void gfx_pal_set(uint8_t pal_num, uint8_t idx,
+                 uint8_t r, uint8_t g, uint8_t b)
+{
+    uint8_t entry[4];
+    entry[0] = b;
+    entry[1] = g;
+    entry[2] = r;
+    entry[3] = 0;
+    gfx_pal_load(pal_num, idx, 1, entry);
+}
+
+void gfx_pal_get(uint8_t pal_num, uint8_t start, uint8_t count,
+                 uint8_t *data)
+{
+    pal_get(pal_num, start, count, data);
+}
+
+void gfx_pal_get_color(uint8_t pal_num, uint8_t idx,
+                       uint8_t *r, uint8_t *g, uint8_t *b)
+{
+    pal_get_color(pal_num, idx, r, g, b);
+}
+
+void gfx_pal_reset(void)
+{
+    pal_reset(PAL_GRAPH);
+}