From 1f5d00fe55aab2349733c726065082c41b80ee40 Mon Sep 17 00:00:00 2001
From: GreaseMonkey <thematrixeatsyou@gmail.com>
Date: Tue, 21 Nov 2023 10:26:13 +1300
Subject: [PATCH] Generate CGA-to-EGA tables in video.c; Remove redundant table
 generation in vid_ega.c

---
 src/include/86box/vid_svga_render.h |  1 +
 src/video/vid_ega.c                 | 28 ----------------------------
 src/video/video.c                   | 13 +++++++++++++
 3 files changed, 14 insertions(+), 28 deletions(-)

diff --git a/src/include/86box/vid_svga_render.h b/src/include/86box/vid_svga_render.h
index 0c48303c9..3ad9e401c 100644
--- a/src/include/86box/vid_svga_render.h
+++ b/src/include/86box/vid_svga_render.h
@@ -34,6 +34,7 @@ extern int      cgablink;
 extern int scrollcache;
 
 extern uint8_t edatlookup[4][4];
+extern uint8_t egaremap2bpp[256];
 
 void svga_recalc_remap_func(svga_t *svga);
 
diff --git a/src/video/vid_ega.c b/src/video/vid_ega.c
index 957a81304..d4abebb39 100644
--- a/src/video/vid_ega.c
+++ b/src/video/vid_ega.c
@@ -61,8 +61,6 @@ static uint32_t        pallook64[256];
 static int             ega_type           = 0;
 static int             old_overscan_color = 0;
 
-uint8_t egaremap2bpp[256];
-
 /* 3C2 controls default mode on EGA. On VGA, it determines monitor type (mono or colour):
     7=CGA mode (200 lines), 9=EGA mode (350 lines), 8=EGA mode (200 lines). */
 int egaswitchread;
@@ -1282,32 +1280,6 @@ ega_init(ega_t *ega, int monitor_type, int is_mono)
         }
     }
 
-    for (c = 0; c < 4; c++) {
-        for (d = 0; d < 4; d++) {
-            edatlookup[c][d] = 0;
-            if (c & 1)
-                edatlookup[c][d] |= 1;
-            if (d & 1)
-                edatlookup[c][d] |= 2;
-            if (c & 2)
-                edatlookup[c][d] |= 0x10;
-            if (d & 2)
-                edatlookup[c][d] |= 0x20;
-        }
-    }
-
-    for (c = 0; c < 256; c++) {
-        egaremap2bpp[c] = 0;
-        if (c & 0x01)
-            egaremap2bpp[c] |= 0x01;
-        if (c & 0x04)
-            egaremap2bpp[c] |= 0x02;
-        if (c & 0x10)
-            egaremap2bpp[c] |= 0x04;
-        if (c & 0x40)
-            egaremap2bpp[c] |= 0x08;
-    }
-
     if (is_mono) {
         for (c = 0; c < 256; c++) {
             if (((c >> 3) & 3) == 0)
diff --git a/src/video/video.c b/src/video/video.c
index 34e602e39..4c561e229 100644
--- a/src/video/video.c
+++ b/src/video/video.c
@@ -78,6 +78,7 @@
 
 volatile int screenshots = 0;
 uint8_t      edatlookup[4][4];
+uint8_t      egaremap2bpp[256];
 uint8_t      fontdat[2048][8];            /* IBM CGA font */
 uint8_t      fontdatm[2048][16];          /* IBM MDA font */
 uint8_t      fontdat2[2048][8];           /* IBM CGA 2nd instance font */
@@ -915,6 +916,18 @@ video_init(void)
         }
     }
 
+    for (uint16_t c = 0; c < 256; c++) {
+        egaremap2bpp[c] = 0;
+        if (c & 0x01)
+            egaremap2bpp[c] |= 0x01;
+        if (c & 0x04)
+            egaremap2bpp[c] |= 0x02;
+        if (c & 0x10)
+            egaremap2bpp[c] |= 0x04;
+        if (c & 0x40)
+            egaremap2bpp[c] |= 0x08;
+    }
+
     video_6to8 = malloc(4 * 256);
     for (uint16_t c = 0; c < 256; c++)
         video_6to8[c] = calc_6to8(c);