TheIndustriousRabbit/vga-logic-processor-examples
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more latch copy fun, write asm kb interrupt handler bc why not

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This commit is contained in:
John Bintz 2024-03-20 09:02:47 -04:00
parent 51625bb432
commit 4f85bd4b1b
2 changed files with 111 additions and 11 deletions
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43
main.c
View File

@ -1,22 +1,29 @@
#include <stdio.h>
#include <i86.h>
#include <conio.h>
extern void __cdecl enableUnchainedVGAMode();
extern void __cdecl enableTextMode();
extern void __cdecl fillScreen(int);
extern void __cdecl latchCopyCube();
extern void __cdecl latchCopyCube(char offset, int writtenValue, int writeMode);
extern int __cdecl paramTest(int wow);
extern void __cdecl far interrupt keyboardHandler();
extern char keyboardPressed;
char far *VGA = (char*)0xA0000;
#define PLANE_WIDTH (320 / 4)
void far (interrupt *int9Save)();
void populateExampleCube(void) {
int y, x;
outp(0x3c4, 0x02);
for (y = 0; y < 15; ++y) {
for (x = 0; x < 15; ++x) {
for (y = 0; y < 16; ++y) {
for (x = 0; x < 16; ++x) {
outp(0x3c5, 1 << (x % 4));
VGA[y * PLANE_WIDTH + x / 4] = y * 16 + x;
}
@ -34,14 +41,40 @@ int main(void) {
int i,j;
int9Save = _dos_getvect(9);
_dos_setvect(9, keyboardHandler);
printf("%p\n", keyboardHandler);
while (keyboardPressed == 0) {
printf("%d\n", keyboardPressed);
}
printf("wow\n");
delay(200);
_dos_setvect(9, int9Save);
return 0;
enableUnchainedVGAMode();
fillScreen(0);
populateExampleCube();
latchCopyCube();
latchCopyCube(8, 0, 0x00);
latchCopyCube(12, 127, 0x00);
latchCopyCube(16, 0, 0x08);
latchCopyCube(20, 127, 0x08);
latchCopyCube(24, 0, 0x10);
latchCopyCube(28, 127, 0x10);
latchCopyCube(32, 0, 0x18);
latchCopyCube(36, 127, 0x18);
while (keyboardPressed == 0) {
delay(1);
}
delay(2000);
/*

79
vga.asm
View File

@ -2,6 +2,9 @@ PUBLIC _enableUnchainedVGAMode
PUBLIC _enableTextMode
PUBLIC _fillScreen
PUBLIC _latchCopyCube
PUBLIC _paramTest
PUBLIC _keyboardPressed
PUBLIC _keyboardHandler
DISPLAY_MODE_VGA equ 13h
DISPLAY_MODE_TEXT equ 03h
@ -23,8 +26,42 @@ VGA_CRT_CONTROLLER_MODE_CONTROL equ 0x17
.386
.model flat,c
.DATA
_keyboardPressed dd 0
.CODE
_keyboardHandler:
cli
push eax
push ebx
in al, 0x60
mov bl, al
; acknowledge keyboard
in al, 0x61
mov ah, al
or al, 0x80
out 0x61, al
xchg ah, al
out 0x61, al
and bl,0x80
jne _keyboardHandler_notKeydown
mov [_keyboardPressed], 1
_keyboardHandler_notKeydown:
; acknowledge interrupt
mov al, 0x20
out 0x20, al
pop ebx
pop eax
sti
iretd
_enableUnchainedVGAMode:
mov ax,0x0013;
int 0x10
@ -76,24 +113,49 @@ _fillScreen_loop:
ret
_paramTest:
push ebp
mov ebp,esp
mov eax,0
mov al, BYTE PTR [ebp+8]
mov esp,ebp
pop ebp
ret
_latchCopyCube:
push ebp
mov ebp,esp
; we need a y variable
sub esp,4 ; y
; enable latch reads
push edx
push ebx
; accept a mode
; accept a mix value
; accept an x offset
; [ebp+8] is x offset
; [ebp+12] is written value
; [ebp+16] is data rotate register
; enable latch reads on all planes
mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
mov al, VGA_SEQUENCE_CONTROLLER_MAP_MASK_MODE
mov ah, 0xf
out dx, ax
; enable OR writes
mov dx, VGA_GRAPHICS_MODE_INDEX
mov al, 0x08
mov ah, 0x00
mov al, 0x03
mov ah, [ebp+16]
out dx, ax
mov DWORD PTR [ebp-4],16
mov dh, [ebp+12]
mov DWORD PTR [ebp-4],16 ; y
; read across the cube, should take 4 * 16 reads
mov cx,[ebp-4]
_latchCopyCube_yLoop:
@ -106,14 +168,17 @@ _latchCopyCube_yLoop:
mul bl ; number of lines
add eax,0xa0000 ; vga base address
; keep our index handy
mov ebx, [ebp+8]
; start x loop
mov cx,4
_latchCopyCube_xLoop:
; fill latches via memory read
mov bl, BYTE PTR [eax]
mov dl, BYTE PTR [eax]
; write blank
mov [eax+12],0
mov BYTE PTR [eax+ebx], dh
; increment vga pointer
inc eax
@ -128,6 +193,8 @@ _latchCopyCube_xLoop:
loop _latchCopyCube_yLoop
; put things back
pop ebx
pop edx
mov esp,ebp
pop ebp
ret