mdview2: add render-cache markdown viewer (Phases 0-4)

New examples/mdview2 — render-cache version of mdview: each logical line is rendered into an EMM (char,attr) buffer once during file load (interleaved with index_lines()), then scrolling draws straight from the cache via ESTEX WINREST, with no re-parsing or fb() access in the steady state. Horizontal scroll still uses the old live-render path (Phase 5, not yet migrated). Format and budget were derisked empirically first (tests/winrest): confirmed ESTEX WINCOPY/WINREST buffer layout and measured EMM free space, both folded into the implementation. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-06-23 22:41:32 +03:00
parent 1b39a60ff0
commit eab5a2d6ac
6 changed files with 3034 additions and 0 deletions
@@ -0,0 +1,151 @@
+/*
+ * Probe for ESTEX WINCOPY (59h) / WINREST (5Ah) — "save/restore screen
+ * window" calls (docs/part2/DSS 1.60 rst 10.txt:1379-1417):
+ *
+ *   D=row  E=col  H=height  L=width  B=buffer page  IX=buffer address
+ *
+ * Goal: reverse-engineer the on-disk cell format (char/attr order,
+ * per-row stride/padding) by writing four DISTINCT (char,attr) cells,
+ * capturing them with WINCOPY, and hex-dumping the captured page.
+ * A second WINREST to a different screen location confirms the
+ * round-trip visually.
+ *
+ * Register layout verified via `sdcc -S` for win_copy(row,col,h,w,page):
+ *   A=row, L=col, stack [SP+2]=h [SP+3]=w [SP+4]=page (sdcccall(1)).
+ *
+ * CONFIRMED in MAME (2026-06-23): buffer format is (char,attr) pairs,
+ * row-major, stride = width*2 bytes, no padding. See memory note
+ * sprinter_winrest_format.
+ *
+ * Also reports mem_info() (total/free 16 KB EMM pages) at program
+ * start, to size a future mdview2 pre-render cache budget.
+ */
+#include <stdio.h>
+#include <stdint.h>
+#include <conio.h>
+#include <sprinter.h>
+#include <sprinter_mem.h>
+
+#define BUF_ADDR 0xC000u
+
+static void win_copy(uint8_t row, uint8_t col, uint8_t h, uint8_t w, uint8_t page) __naked
+{
+    (void)row; (void)col; (void)h; (void)w; (void)page;
+    __asm
+        ld    iy, #2
+        add   iy, sp
+        ld    d, a              ; D = row
+        ld    e, l              ; E = col
+        ld    h, 0 (iy)         ; H = height
+        ld    a, 1 (iy)         ; width -> L
+        ld    l, a
+        ld    a, 2 (iy)         ; page -> B
+        ld    b, a
+        push  ix
+        ld    ix, #0xC000
+        ld    c, #0x59          ; ESTEX WINCOPY
+        di
+        rst   #0x10
+        ei
+        pop   ix
+        pop   hl                ; return address
+        inc   sp
+        inc   sp
+        inc   sp                ; discard h,w,page
+        jp    (hl)
+    __endasm;
+}
+
+static void win_rest(uint8_t row, uint8_t col, uint8_t h, uint8_t w, uint8_t page) __naked
+{
+    (void)row; (void)col; (void)h; (void)w; (void)page;
+    __asm
+        ld    iy, #2
+        add   iy, sp
+        ld    d, a              ; D = row
+        ld    e, l              ; E = col
+        ld    h, 0 (iy)         ; H = height
+        ld    a, 1 (iy)         ; width -> L
+        ld    l, a
+        ld    a, 2 (iy)         ; page -> B
+        ld    b, a
+        push  ix
+        ld    ix, #0xC000
+        ld    c, #0x5A          ; ESTEX WINREST
+        di
+        rst   #0x10
+        ei
+        pop   ix
+        pop   hl
+        inc   sp
+        inc   sp
+        inc   sp
+        jp    (hl)
+    __endasm;
+}
+
+int main(void)
+{
+    clrscr();
+
+    /* --- mem_info() baseline, before any allocation by this program. */
+    uint16_t total_pages = 0, free_pages = 0;
+    mem_info(&total_pages, &free_pages);
+
+    textattr(0x0F);
+    gotoxy(0, 0);
+    printf("EMM pages: total=%u free=%u (each = 16 KB)\n", total_pages, free_pages);
+    printf("  => total %lu KB, free %lu KB\n",
+           (uint32_t)total_pages * 16UL, (uint32_t)free_pages * 16UL);
+    printf("Press a key to continue to WINCOPY/WINREST probe...\n");
+    (void)getchar();
+
+    /* Four distinguishable cells: char and attr both easy to recognise
+     * in a hex dump (A/B/C/D = 0x41..0x44, attrs 0x11/0x22/0x33/0x44). */
+    gotoxy(5, 10);  textattr(0x11); putch('A');
+    gotoxy(6, 10);  textattr(0x22); putch('B');
+    gotoxy(5, 11);  textattr(0x33); putch('C');
+    gotoxy(6, 11);  textattr(0x44); putch('D');
+
+    textattr(0x0F);
+    gotoxy(0, 13);
+    printf("Captured window drawn above (row 10-11, col 5-6).\n");
+    printf("Press a key to WINCOPY it...\n");
+    (void)getchar();
+
+    uint8_t blk  = mem_alloc_pages(1);
+    uint8_t page = mem_get_page(blk, 0);
+
+    win_copy(10, 5, 2, 2, page);
+
+    /* Map the same physical page into our own W3 to inspect the bytes
+     * WINCOPY just wrote there. */
+    sprinter_page_w3(page);
+    {
+        volatile uint8_t *buf = (volatile uint8_t *)BUF_ADDR;
+        gotoxy(0, 15);
+        printf("Buffer dump (first 16 bytes of page %u):\n", page);
+        for (uint8_t i = 0; i < 16; i++) {
+            printf("%02X ", buf[i]);
+        }
+        printf("\n");
+        for (uint8_t i = 0; i < 16; i++) {
+            char c = (char)buf[i];
+            putchar((c >= 0x20 && c < 0x7F) ? c : '.');
+        }
+        printf("\n");
+    }
+
+    printf("Press a key to WINREST it to row 20...\n");
+    (void)getchar();
+
+    win_rest(20, 5, 2, 2, page);
+
+    gotoxy(0, 23);
+    printf("Restored at row 20-21, col 5-6 -- compare colours/chars\n");
+    printf("with the original at row 10-11.\n");
+    printf("Press a key to exit...\n");
+    (void)getchar();
+
+    return 0;
+}