initial commit

.gitignore

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+*.o
+*.err
+*.exe

main.c

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+#include <i86.h>
+#include <conio.h>
+
+extern void __cdecl enableUnchainedVGAMode();
+extern void __cdecl enableTextMode();
+
+char far *VGA = (char*)0xA0000;
+
+int main(void) {
+  // activate unchained vga mode
+  // set up 8 very clear colors
+  // place some data into video memory to be latch copied
+  // show off the following
+  // * latch copies
+  // * masking
+  // * barrel shifting
+
+  int i,j;
+
+  enableUnchainedVGAMode();
+
+  outp(0x3c4, 0x02);
+
+  for (i = 0; i < 200; ++i) {
+    for (j = 0; j < 4; ++j) {
+      outp(0x3c5, 1 << j);
+      VGA[i] = j + 1;
+    }
+  }
+
+  delay(5000);
+
+  enableTextMode();
+}

makefile

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+obj = vga.o main.o
+
+.c.o:
+	wcc386 -q -bt=dos $<
+
+.asm.o:
+	wasm $<
+
+main.exe: $(obj)
+	wcl386 -fe=main -bt=dos -l=dos4g $(obj)

run

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+#!/bin/sh
+
+wmake -h && dosbox-x -nolog main.exe

setup.sh

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+export WATCOM=~/Applications/open-watcom-v2/rel
+export INCLUDE=$WATCOM/h
+export LIB=$WATCOM/lib286/dos:$WATCOM/lib286
+export PATH=$WATCOM/binl64:$WATCOM/binl:$PATH
+

vga.asm

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+PUBLIC _enableUnchainedVGAMode
+PUBLIC _enableTextMode
+
+DISPLAY_MODE_VGA equ 13h
+DISPLAY_MODE_TEXT equ 03h
+
+VGA_SEQUENCE_CONTROLLER_INDEX equ 0x3c4
+VGA_SEQUENCE_CONTROLLER_DATA equ 0x3c5h
+VGA_SEQUENCE_CONTROLLER_MEMORY_MODE equ 0x04
+
+VGA_CRT_CONTROLLER_INDEX equ 0x03d4
+VGA_CRT_CONTROLLER_DATA equ 0x03d5
+VGA_CRT_CONTROLLER_UNDERLINE_LOC equ 0x14
+VGA_CRT_CONTROLLER_MODE_CONTROL equ 0x17
+
+.386
+.model flat,c
+
+.CODE
+
+_enableUnchainedVGAMode:
+  mov ax,0x0013;
+  int 0x10
+
+  mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
+  mov al, VGA_SEQUENCE_CONTROLLER_MEMORY_MODE
+  mov ah, 0x06
+  out dx, ax
+
+  mov dx, VGA_CRT_CONTROLLER_INDEX
+  mov al, VGA_CRT_CONTROLLER_MODE_CONTROL
+  mov ah, 0xe3
+  out dx, ax
+
+  mov dx, VGA_CRT_CONTROLLER_INDEX
+  mov al, VGA_CRT_CONTROLLER_UNDERLINE_LOC
+  mov ah, 0x00
+  out dx, ax
+
+  ret
+
+_enableTextMode:
+  mov ah,0h
+  mov al,DISPLAY_MODE_TEXT
+  int 10h
+  ret
+
+end