ah OK that byte is OK to occupy

it's probably microscopically faster

Makefile

@@ -56,7 +56,10 @@ DISP_WIDTH ?= 512
 DISP_HEIGHT ?= 342
 CFLAGS_CFG = -DDISP_WIDTH=$(DISP_WIDTH) -DDISP_HEIGHT=$(DISP_HEIGHT)
 
-all:	main
+all:	main patcher
+
+patcher: src/rom.c
+	$(CC) $(CFLAGS) -DUMAC_STANDALONE_PATCHER -o $@ $<
 
 $(MUSASHI_SRC): $(MUSASHI)/m68kops.h
 
@@ -74,7 +77,7 @@ main:	$(OBJS)
 
 clean:
 	make -C $(MUSASHI) clean
-	rm -f $(MY_OBJS) main
+	rm -f $(MY_OBJS) main patcher
 
 ################################################################################
 # Mac driver sources (no need to generally rebuild

src/rom.c

@@ -55,6 +55,18 @@ static const uint8_t sony_driver[] = {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+
+static int      rom_patch1(uint8_t *rom_base, int disp_width, int disp_height, int mem_size);
+#if !defined(UMAC_STANDALONE_PATCHER)
+int      rom_patch(uint8_t *rom_base) {
+        return rom_patch1(rom_base, DISP_WIDTH, DISP_HEIGHT, UMAC_MEMSIZE * 1024);
+}
+#endif
+
+#undef DISP_WIDTH
+#undef DISP_HEIGHT
+#undef UMAC_MEMSIZE
+
 static uint32_t rom_get_version(uint8_t *rom_base)
 {
 #if BYTE_ORDER == LITTLE_ENDIAN
@@ -80,7 +92,7 @@ static uint32_t rom_get_version(uint8_t *rom_base)
         } while (0)
 
 
-static void     rom_patch_plusv3(uint8_t *rom_base)
+static int     rom_patch_plusv3(uint8_t *rom_base, int disp_width, int disp_height, int ram_size)
 {
         /* Inspired by patches in BasiliskII!
          */
@@ -100,13 +112,13 @@ static void     rom_patch_plusv3(uint8_t *rom_base)
          * - No IWM init
          * - new Sound?
          */
-#if UMAC_MEMSIZE > 128 && UMAC_MEMSIZE < 512
+        if (ram_size > 128*1024 && ram_size < 512*1024) {
                 /* Hack to change memtop: try out a 256K Mac :) */
                 for (int i = 0x376; i < 0x37e; i += 2)
                         ROM_WR16(i, M68K_INST_NOP);
-        ROM_WR16(0x376, 0x2a7c); // moveal #RAM_SIZE, A5
+                ROM_WR16(0x376, 0x2a7c); // moveal #ram_size, A5
-        ROM_WR16(0x378, RAM_SIZE >> 16);
+                ROM_WR16(0x378, ram_size >> 16);
-        ROM_WR16(0x37a, RAM_SIZE & 0xffff);
+                ROM_WR16(0x37a, ram_size & 0xffff);
                 /* That overrides the probed memory size, but
                  * P_ChecksumRomAndTestMemory returns a failure code for
                  * things that aren't 128/512.  Skip that:
@@ -116,17 +128,17 @@ static void     rom_patch_plusv3(uint8_t *rom_base)
                  * allowing the ROM checksum to fail (it returns failure, then
                  * we carry on).  This avoids wild RAM addrs being accessed.
                  */
-#endif
 
-#if DISP_WIDTH != 512 || DISP_HEIGHT != 342
+                /* Fix up the sound buffer as used by BootBeep */
-#define SCREEN_SIZE                     (DISP_WIDTH*DISP_HEIGHT/8)
+                ROM_WR32(0x292, ram_size - 768);
-#define SCREEN_DISTANCE_FROM_TOP        (SCREEN_SIZE + 0x380)
+        }
-#if (SCREEN_DISTANCE_FROM_TOP >= 65536)
+
-#error "rom.c: Screen res patching maths won't work for a screen this large"
+        if(disp_width != 512 || disp_height != 342) {
-#endif
+                int screen_size = (disp_width*disp_height/8);
-#define SCREEN_BASE                     (0x400000-SCREEN_DISTANCE_FROM_TOP)
+                int screen_distance_from_top = screen_size + 0x380;
-#define SCREEN_BASE_L16                 (SCREEN_BASE & 0xffff)
+                int screen_base = 0x400000-screen_distance_from_top;
-#define SBCOORD(x, y)                   (SCREEN_BASE + ((DISP_WIDTH/8)*(y)) + ((x)/8))
+printf("screen size=%d screen_base=%x\n", screen_size, screen_base);
+#define SBCOORD(x, y)                   (screen_base + ((disp_width/8)*(y)) + ((x)/8))
 
                 /* Changing video res:
                  *
@@ -134,7 +146,7 @@ static void     rom_patch_plusv3(uint8_t *rom_base)
                  * buffer lands underneath sound/other buffers at top of mem,
                  * i,e, 0x3fa700 = 0x400000-0x5580-0x380.  So any new buffer
                  * will be placed (and read out from for the GUI) at
-         * MEM_TOP-0x380-SCREEN_SIZE.
+                 * MEM_TOP-0x380-screen_size.
                  *
                  * For VGA, size is 0x9600 bytes (0x2580 words)
                  */
@@ -148,11 +160,43 @@ static void     rom_patch_plusv3(uint8_t *rom_base)
                 /* Now 0x46-0x57 can be used */
                 unsigned int patch_0 = 0x46;
                 ROM_WR16(patch_0 + 0, 0x9bfc);          /* suba.l #imm32, A5 */
-        ROM_WR16(patch_0 + 2, 0);               /* (Could add more here) */
+                ROM_WR32(patch_0 + 2, screen_distance_from_top);
-        ROM_WR16(patch_0 + 4, SCREEN_DISTANCE_FROM_TOP);
                 ROM_WR16(patch_0 + 6, 0x6000);          /* bra */
                 ROM_WR16(patch_0 + 8, 0x3a4 - (patch_0 + 8));   /* Return to 3a4 */
 
+                // Additional patches needed if DISP_WIDTH is 1024 or above
+
+                unsigned int patch_2 = 0x32;
+                unsigned int patch_1 = patch_0 + 10;
+                if ((disp_width / 8) >= 128) {
+                        ROM_WR16(patch_1 + 0, 0x3a3c);           /* move.l ..., D5 */
+                        ROM_WR16(patch_1 + 2, disp_width / 8);   /*        ^^^ */
+                        ROM_WR16(patch_1 + 4, 0xc2c5);           /* mulu D5, D1 */
+                        ROM_WR16(patch_1 + 6, 0x4e75);           /* rts */
+                        if (patch_1 + 8 > 0x58) {
+                            RERR("patch_1 extends too far (0x%x > 0x58)\n", patch_1 + 8);
+                            return -1;
+                        }
+
+                        // is this the illegal instruction handler entry? if it is, it
+                        // eventually falls through to 'check if test software exists',
+                        // below.... @sc's annotated disassembly suggests "never called by the mac plus"
+                        // but it looks to me like 0x2e is in the vector table at 0x16...
+                        // patch it to jump down to after the test software check too.
+                        ROM_WR16(0x2e, 0x6000);                 /* bra */
+                        ROM_WR16(0x30, 0x62-0x30);              /* offset */
+
+                        ROM_WR16(patch_2 + 0, 0x303c);           /* move.l ..., D0 */
+                        ROM_WR16(patch_2 + 2, disp_width / 8);   /*        ^^^ */
+                        ROM_WR16(patch_2 + 4, 0x41f8);           /* Lea.L     (CrsrSave), A0 */
+                        ROM_WR16(patch_2 + 6, 0x088c);           /*            ^^^^^^^^ */
+                        ROM_WR16(patch_2 + 8, 0x4e75);           /* rts */
+                        if (patch_2 + 10 > 0x41) {
+                                RERR("patch_2 extends too far (0x%x > 0x41)\n", patch_2);
+                                return -1;
+                        }
+                }
+
                 /* Magic screen-related locations in Mac Plus ROM 4d1f8172:
                  *
                  * 8c : screen base addr (usually 3fa700, now 3f6680)
@@ -185,19 +229,19 @@ static void     rom_patch_plusv3(uint8_t *rom_base)
                  * 1e6e : x
                  * 1e82 : y
                  */
-        ROM_WR16(0x8c, SCREEN_BASE_L16);
+                ROM_WR32(0x8a, screen_base);
-        ROM_WR16(0x148, SCREEN_BASE_L16);
+                ROM_WR32(0x146, screen_base);
-        ROM_WR32(0x164, SBCOORD(DISP_WIDTH/2 - (48/2), DISP_HEIGHT/2 + 8));
+                ROM_WR32(0x164, SBCOORD(disp_width/2 - (48/2), disp_height/2 + 8));
-        ROM_WR16(0x188, DISP_WIDTH/8);
+                ROM_WR16(0x188, disp_width/8);
-        ROM_WR16(0x194, DISP_WIDTH/8);
+                ROM_WR16(0x194, disp_width/8);
-        ROM_WR16(0x19c, (6*DISP_WIDTH/8)-1);
+                ROM_WR16(0x19c, (6*disp_width/8)-1);
-        ROM_WR32(0x1a4, SBCOORD(DISP_WIDTH/2 - 8, DISP_HEIGHT/2 + 8 + 8));
+                ROM_WR32(0x1a4, SBCOORD(disp_width/2 - 8, disp_height/2 + 8 + 8));
-        ROM_WR16(0x1ee, (SCREEN_SIZE/4)-1);
+                ROM_WR16(0x1ee, (screen_size/4)-1);
 
-        ROM_WR32(0xf0c, SBCOORD(DISP_WIDTH/2 - 16, DISP_HEIGHT/2 - 26));
+                ROM_WR32(0xf0c, SBCOORD(disp_width/2 - 16, disp_height/2 - 26));
-        ROM_WR32(0xf18, SBCOORD(DISP_WIDTH/2 - 8, DISP_HEIGHT/2 - 20));
+                ROM_WR32(0xf18, SBCOORD(disp_width/2 - 8, disp_height/2 - 20));
-        ROM_WR32(0x7e0, SBCOORD(DISP_WIDTH/2 - 16, DISP_HEIGHT/2 - 26));
+                ROM_WR32(0x7e0, SBCOORD(disp_width/2 - 16, disp_height/2 - 26));
-        ROM_WR32(0x7f2, SBCOORD(DISP_WIDTH/2 - 8, DISP_HEIGHT/2 - 11));
+                ROM_WR32(0x7f2, SBCOORD(disp_width/2 - 8, disp_height/2 - 11));
 
                 /* Patch "SubA #$5900, A5" to subtract 0x9880.
                  * However... can't just patch the int16 immediate, as that's
@@ -209,29 +253,46 @@ static void     rom_patch_plusv3(uint8_t *rom_base)
                 ROM_WR16(0x3a0, 0x6000);                /* bra */
                 ROM_WR16(0x3a2, patch_0 - 0x3a2);       /* ...to patch0, returns at 0x3a4 */
 
-        ROM_WR16(0x474, DISP_WIDTH/8);
+                ROM_WR16(0x474, disp_width/8);
-        ROM_WR16(0x494, DISP_HEIGHT);
+                ROM_WR16(0x494, disp_height);
-        ROM_WR16(0x498, DISP_WIDTH);
+                ROM_WR16(0x498, disp_width);
-        ROM_WR16(0xa0e, DISP_HEIGHT);           /* copybits? */
+                ROM_WR16(0xa0e, disp_height);           /* copybits? */
-        ROM_WR16(0xa10, DISP_WIDTH);
+                ROM_WR16(0xa10, disp_width);
-        ROM_WR16(0xee2, (DISP_WIDTH/8)-4);      /* tPutIcon bytes per row, minus 4 */
+                ROM_WR16(0xee2, (disp_width/8)-4);      /* tPutIcon bytes per row, minus 4 */
-        ROM_WR16(0xef2, DISP_WIDTH/8);          /* tPutIcon bytes per row */
+                ROM_WR16(0xef2, disp_width/8);          /* tPutIcon bytes per row */
-        ROM_WR16(0xf36, (DISP_WIDTH/8)-2);      /* tPutIcon bytes per row, minus 2 */
+                ROM_WR16(0xf36, (disp_width/8)-2);      /* tPutIcon bytes per row, minus 2 */
-        ROM_WR8(0x1cd1, DISP_WIDTH/8);          /* hidecursor */
+
-        ROM_WR16(0x1d48, DISP_WIDTH-32);        /* 1d46+2 was originally 512-32 rite? */
+                // getting the stride of the framebuffer for hidecursor
-        ROM_WR16(0x1d4e, DISP_WIDTH-32);        /* 1d4c+2 is 480, same */
+                if ((disp_width / 8) >= 128) {
-        ROM_WR16(0x1d6e, DISP_HEIGHT-16);       /* showcursor (YESS fixed Y crash bug!) */
+                        ROM_WR16(0x1ccc, 0x4eba);               /* (hidecursor) jsr */
-        ROM_WR16(0x1d74, DISP_HEIGHT);          /* showcursor */
+                        ROM_WR16(0x1cce, patch_2 - 0x1cce);     /* .. to patch2, returns at 1cd0 */
-        ROM_WR8(0x1d93, DISP_WIDTH/8);          /* showcursor */
+                        ROM_WR16(0x1cd0, 0x4e71);               /* nop */
-        ROM_WR16(0x1e68, DISP_HEIGHT);          /* mScrnSize */
+                } else {
-        ROM_WR16(0x1e6e, DISP_WIDTH);           /* mScrnSize */
+                        ROM_WR8(0x1cd1, disp_width/8);         /* hidecursor */
-        ROM_WR16(0x1e82, DISP_HEIGHT);          /* tScrnBitMap */
+                }
+
+                ROM_WR16(0x1d48, disp_width-32);        /* 1d46+2 was originally 512-32 rite? */
+                ROM_WR16(0x1d4e, disp_width-32);        /* 1d4c+2 is 480, same */
+                ROM_WR16(0x1d6e, disp_height-16);       /* showcursor (YESS fixed Y crash bug!) */
+                ROM_WR16(0x1d74, disp_height);          /* showcursor */
+                ROM_WR8(0x1d93, disp_width/8);          /* showcursor */
+                ROM_WR16(0x1e68, disp_height);          /* mScrnSize */
+                // getting the stride of the framebuffer for showcursor
+                if ((disp_width / 8) >= 128) {
+                        ROM_WR16(0x1d92, 0x4eba);               /* jsr */
+                        ROM_WR16(0x1d94, patch_1 - 0x1d94);     /* .. to patch1, returns at 1d96 */
+                } else {
+                        ROM_WR8(0x1d93, disp_width/8);          /* showcursor */
+                }
+                ROM_WR16(0x1e6e, disp_width);           /* mScrnSize */
+                ROM_WR16(0x1e82, disp_height);          /* tScrnBitMap */
+        }
 
         /* FIXME: Welcome To Macintosh is drawn at the wrong position. Find where that's done. */
-#endif
+        return 0;
 }
 
-int      rom_patch(uint8_t *rom_base)
+static int      rom_patch1(uint8_t *rom_base, int disp_width, int disp_height, int mem_size)
 {
         uint32_t v = rom_get_version(rom_base);
         int r = -1;
@@ -239,8 +300,7 @@ int      rom_patch(uint8_t *rom_base)
          */
         switch(v) {
         case ROM_PLUSv3_VERSION:
-                rom_patch_plusv3(rom_base);
+                r = rom_patch_plusv3(rom_base, disp_width, disp_height, mem_size);
-                r = 0;
                 break;
 
         default:
@@ -250,3 +310,99 @@ int      rom_patch(uint8_t *rom_base)
         return r;
 }
 
+#if defined(UMAC_STANDALONE_PATCHER)
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main(int argc, char **argv) {
+        uint8_t *rom_base;
+        char *rom_filename = "4D1F8172 - MacPlus v3.ROM";
+        char *rom_dump_filename = NULL; // Raw bytes
+        char *rom_header_filename = NULL; // C header
+        int ch;
+        int disp_width = 512;
+        int disp_height = 342;
+        int ram_size = 128;
+
+        while ((ch = getopt(argc, argv, "vm:r:w:W:")) != -1) {
+                switch (ch) {
+                case 'v':
+                        disp_width = 640;
+                        disp_height = 480;
+                        break;
+                case 'm':
+                        ram_size = atoi(optarg);
+                        break;
+                case 'r':
+                        rom_filename = strdup(optarg);
+                        break;
+                case 'W':
+                        rom_dump_filename = strdup(optarg);
+                        break;
+                case 'w':
+                        rom_header_filename = strdup(optarg);
+                        break;
+                case '?':
+                        abort();
+                }
+        }
+        if (!rom_dump_filename && !rom_header_filename) {
+                printf("Must specify either a -W (binary) or -w (C header) output file");
+                abort();
+        }
+        printf("Opening ROM '%s'\n", rom_filename);
+        int ofd = open(rom_filename, O_RDONLY);
+        if (ofd < 0) {
+                perror("ROM");
+                return 1;
+        }
+
+        struct stat sb;
+        fstat(ofd, &sb);
+        off_t _rom_size = sb.st_size;
+        rom_base = mmap(0, _rom_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, ofd, 0);
+        if (rom_base == MAP_FAILED) {
+                printf("Can't mmap ROM!\n");
+                return 1;
+        }
+        if (rom_patch1(rom_base, disp_width, disp_height, ram_size*1024)) {
+                printf("Failed to patch ROM\n");
+                return 1;
+        }
+        if (rom_dump_filename) {
+                int rfd = open(rom_dump_filename, O_CREAT | O_TRUNC | O_RDWR, 0655);
+                if (rfd < 0) {
+                        perror("ROM dump");
+                        return 1;
+                }
+                ssize_t written = write(rfd, rom_base, _rom_size);
+                if (written < 0) {
+                        perror("ROM dump write");
+                        return 1;
+                }
+                if (written < _rom_size) {
+                        printf("*** WARNING: Short write to %s!\n",
+                               rom_dump_filename);
+                } else {
+                        printf("Dumped ROM to %s\n", rom_dump_filename);
+                }
+                close(rfd);
+        }
+        if (rom_header_filename) {
+            FILE *ofd = fopen(rom_header_filename, "w");
+            if (!ofd) { perror("fopen"); abort(); }
+            for(off_t i=0; i<_rom_size; i++) {
+                fprintf(ofd, "%d,", rom_base[i]);
+                if(i % 16 == 15) fprintf(ofd, "\n");
+            }
+            fprintf(ofd, "\n");
+            printf("Dumped ROM to %s as header\n", rom_header_filename);
+            fclose(ofd);
+        }
+}
+#endif

src/unix_main.c

@@ -54,7 +54,7 @@ static void     print_help(char *n)
                "\t-i\t\t\tDisassembled instruction trace\n", n);
 }
 
-#define DISP_SCALE      2
+#define DISP_SCALE      (DISP_WIDTH < 800 && DISP_HEIGHT < 600 ? 2 : 1)
 
 static uint32_t framebuffer[DISP_WIDTH*DISP_HEIGHT];