svga works, optimize vga and clean up code
This commit is contained in:
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77c162002b
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135fa6c2e8
7
README.md
Normal file
7
README.md
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@ -0,0 +1,7 @@
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# VGA logic units in 256 colors and SVGA mode usage
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Some code to exercise the four logic units of the VGA card in
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256 color mode, as well as code that gets SVGA mode
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working. Most of this is in C, but some of it's in assembler
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to help me learn assembler better, as well as get comfortable with
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C/asm interop on x86.
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53
bmp.c
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53
bmp.c
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@ -0,0 +1,53 @@
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#include <stdio.h>
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#include <sys/types.h>
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#include "bmp.h"
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#include "vesa.h"
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int readBMPHeader(FILE *fh, struct BMPImage *info) {
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int sizeOfHeader;
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char value;
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unsigned int numberOfUsedColors;
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if ((fgetc(fh) != 'B') || (fgetc(fh) != 'M')) {
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printf("Not a BMP file\n");
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return 1;
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}
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fseek(fh, 12, SEEK_CUR);
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fread(&sizeOfHeader, sizeof(int), 1, fh);
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fread(&info->width, sizeof(int), 1, fh);
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fread(&info->height, sizeof(int), 1, fh);
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fseek(fh, 2, SEEK_CUR);
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fread(&info->bpp, sizeof(int), 1, fh);
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// for gimp, you need to add colors to the color map until it hits
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// 16 colors, then the image will be a 256 color, 8 bpp image
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//
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// https://www.gimp-forum.net/Thread-indexing-into-8-bit?pid=13233#pid13233
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if (info->bpp != 8) return 1;
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fseek(fh, 18, SEEK_CUR);
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fread(&numberOfUsedColors, sizeof(unsigned int), 1, fh);
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printf("used colors: %d\n",numberOfUsedColors);
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if (numberOfUsedColors > 256) return 1;
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// get down to color data
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fseek(fh, 14 + sizeOfHeader, SEEK_SET);
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fread(info->colors, sizeof(struct BMPColor), numberOfUsedColors, fh);
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return 0;
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}
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void bmp256ColorPaletteToVESAColorPalette(struct BMPImage* bmpImage, struct VESAColor colors[]) {
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int i;
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for (i = 0; i < 256; ++i) {
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colors[i].red = bmpImage->colors[i].red >> 2;
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colors[i].green = bmpImage->colors[i].green >> 2;
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colors[i].blue = bmpImage->colors[i].blue >> 2;
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}
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}
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19
bmp.h
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19
bmp.h
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@ -0,0 +1,19 @@
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#pragma pack(push,1)
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struct BMPColor {
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uint8_t blue;
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uint8_t green;
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uint8_t red;
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uint8_t _a;
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};
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struct BMPImage {
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uint16_t width;
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uint16_t height;
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uint16_t bpp;
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struct BMPColor colors[256];
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char *memoryStart;
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uint16_t transparentColor;
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};
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#pragma pack(pop)
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BIN
chkn640.bmp
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BIN
chkn640.bmp
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Binary file not shown.
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After Width: | Height: | Size: 301 KiB |
50
dpmi.c
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50
dpmi.c
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@ -0,0 +1,50 @@
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#include <sys/types.h>
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#include <i86.h>
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#include <dos.h>
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#include "dpmi.h"
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static uint16_t vbeDOSBufferDPMISelector = 0;
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/**
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* This is memory accessible to real-mode x86, so that
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* interrupts can access the data.
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*/
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void *dpmiAllocateDOSMemory(int size) {
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union REGS regs;
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// a paragraph is 16 bytes because why not
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unsigned short sizeParagraphs = (size + 15) >> 4UL;
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regs.w.ax = 0x0100;
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regs.w.bx = sizeParagraphs;
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int386(0x31, ®s, ®s);
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vbeDOSBufferDPMISelector = regs.w.dx;
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return (void *)(((unsigned long)regs.w.ax) << 4UL);
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}
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void dpmiDeallocateDOSMemory() {
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union REGS regs;
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regs.w.ax = 0x0101;
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regs.w.dx = vbeDOSBufferDPMISelector;
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int386(0x31, ®s, ®s);
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}
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/**
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* You only need to use this if you're passing a DPMI-allocated
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* memory struture to an interrupt via ES:DI. Otherwise, a
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* regular int386 call is sufficient.
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*/
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void dpmiInt(int interruptNo, struct dpmiRealModeRegs *rc) {
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union REGS regs;
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// call the DPMI real mode interrupt handler
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regs.w.ax = 0x0300;
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regs.w.bx = interruptNo; // real mode interrupt
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regs.w.cx = 0; // don't mess with our stack
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regs.x.edi = (unsigned int)rc;
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int386(0x31, ®s, ®s);
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}
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18
dpmi.h
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18
dpmi.h
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@ -0,0 +1,18 @@
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#ifndef __DPMI_H__
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#define __DPMI_H__
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#include <sys/types.h>
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#pragma pack(push,1)
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struct dpmiRealModeRegs {
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uint32_t edi,esi,ebp,reserved;
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uint32_t ebx,edx,ecx,eax;
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uint16_t flags,es,ds,fs,gs,ip,cs,sp,ss;
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};
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#pragma paack(pop)
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void *dpmiAllocateDOSMemory(int size);
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void dpmiDeallocateDOSMemory();
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void dpmiInt(int interruptNo, struct dpmiRealModeRegs *);
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#endif
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56
main.c
56
main.c
@ -7,14 +7,14 @@ extern void __cdecl enableUnchainedVGAMode();
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extern void __cdecl enableTextMode();
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extern void __cdecl fillScreen(int);
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extern void __cdecl latchCopyCube(
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char offset,
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int offset,
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int writtenValue,
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int writeMode,
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int setResetRegister,
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int enableSetResetRegister
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);
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extern void __cdecl writeCube(
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char offset,
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int offset,
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int writeMode,
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int setResetRegister,
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int enableSetResetRegister
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@ -23,7 +23,6 @@ extern void __cdecl drawColorCube(
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char offset,
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int color
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);
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extern int __cdecl paramTest(int wow);
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extern void far interrupt keyboardHandler();
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extern char keyboardPressed;
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@ -40,9 +39,9 @@ void populateExampleCube(void) {
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outp(0x3c4, 0x02);
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for (y = 0; y < 16; ++y) {
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for (x = 0; x < 16; ++x) {
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outp(0x3c5, 1 << (x % 4));
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for (y = 0; y < 16; ++y) {
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VGA[y * PLANE_WIDTH + x / 4] = y * 16 + x;
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}
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}
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@ -50,20 +49,20 @@ void populateExampleCube(void) {
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int main(void) {
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// activate unchained vga mode
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// set up 8 very clear colors
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// place some data into video memory to be latch copied
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// show off the following
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// * latch copies
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// * masking
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// * latch copies with logical operators
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// * plane selection
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// * barrel shifting
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int i,j;
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// * set/reset
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int9Save = _dos_getvect(9);
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_dos_setvect(9, keyboardHandler);
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enableUnchainedVGAMode();
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// set a very bright color as the last possible color to make
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// set/reset usage more visible
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outp(0x3c8, 255);
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outp(0x3c9, 63);
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outp(0x3c9, 63);
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@ -71,27 +70,28 @@ int main(void) {
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fillScreen(0);
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/*
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populateExampleCube();
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latchCopyCube(8, 0, 0x00, 0, 0);
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latchCopyCube(12, 127, 0x00, 0, 0);
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latchCopyCube(16, 0, 0x08, 0, 0);
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latchCopyCube(20, 127, 0x08, 0, 0);
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latchCopyCube(24, 0, 0x10, 0, 0);
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latchCopyCube(28, 127, 0x10, 0, 0);
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latchCopyCube(32, 0, 0x18, 0, 0);
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latchCopyCube(36, 127, 0x18, 0, 0);
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latchCopyCube(40, 0, 0x18 + 0x04, 0, 0);
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latchCopyCube(44, 127, 0x18 + 0x04, 0, 0);
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latchCopyCube(64, 0, 0x10, 7, 7);
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latchCopyCube(68, 0, 0x10, 7, 0);
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latchCopyCube(72, 0, 0x10, 0, 7);
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*/
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writeCube(0, 0x10, 0, 0);
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writeCube(4, 0x10, 7, 0);
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writeCube(8, 0x10, 7, 7);
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writeCube(12, 0x10, 0, 7);
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latchCopyCube(80 * 20, 0, 0x00, 0, 0);
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latchCopyCube(80 * 20 + 5, 127, 0x00, 0, 0);
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latchCopyCube(80 * 20 + 10, 0, 0x08, 0, 0);
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latchCopyCube(80 * 20 + 15, 127, 0x08, 0, 0);
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latchCopyCube(80 * 20 + 20, 0, 0x10, 0, 0);
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latchCopyCube(80 * 20 + 25, 127, 0x10, 0, 0);
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latchCopyCube(80 * 20 + 30, 0, 0x18, 0, 0);
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latchCopyCube(80 * 20 + 35, 127, 0x18, 0, 0);
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latchCopyCube(80 * 20 + 40, 127, 0x10, 1, 3);
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latchCopyCube(80 * 40, 0, 0x18 + 0x04, 0, 0);
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latchCopyCube(80 * 40 + 5, 127, 0x18 + 0x04, 0, 0);
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latchCopyCube(80 * 40 + 10, 0, 0x10, 3, 3);
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latchCopyCube(80 * 40 + 15, 0, 0x10, 1, 3);
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latchCopyCube(80 * 40 + 20, 0, 0x10, 0, 3);
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writeCube(5, 0x00, 1, 3);
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writeCube(10, 0x00, 0, 3);
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writeCube(15, 0x00, 3, 0);
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while (keyboardPressed == 0);
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6
makefile
6
makefile
@ -1,4 +1,5 @@
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obj = vga.o main.o
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svga_obj = dpmi.o bmp.o vesa.o svga.o
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.c.o:
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wcc386 -q -bt=dos $<
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@ -8,3 +9,8 @@ obj = vga.o main.o
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main.exe: $(obj)
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wcl386 -fe=main -bt=dos -l=dos4g $(obj)
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svga.exe: $(svga_obj)
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wcl386 -fe=svga -bt=dos -l=dos4g $(svga_obj)
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all: main.exe svga.exe
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102
svga.c
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102
svga.c
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#include <stddef.h>
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#include <stdio.h>
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#include <conio.h>
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#include <dos.h>
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#include <i86.h>
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#include <memory.h>
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#include <sys/types.h>
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/*
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Set up a 640x480x256 Super VGA screen and load a bitmap image into it.
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Wait 10 seconds, then exit the program.
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Since this is going through DOS/4GW, we need to use the DOS Protected
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Mode Interface (DPMI) to work with x86 Real Mode RAM so the VESA
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interrupt functions have a place to accept and dump data.
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There were a lot of scattered examples as to how to get SVGA going, but:
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* most were written in assembler and, while I can read assembler, I don't
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prefer to, especially in the early learning stages of a bunch of new concepts
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* very few of them covered the whole pipeline of query display, then
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set it up, then do something real with it
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So here's this one. Enjoy.
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John
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*/
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// built from a combination of:
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//
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// * http://www.pennelynn.com/Documents/CUJ/HTML/14.08/KREHBIEL/KREHL1.HTM
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// * https://forum.osdev.org/viewtopic.php?f=2&t=30186
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// * https://github.com/joncampbell123/doslib/blob/master/hw/vesa/vesa.c
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// * https://stackoverflow.com/questions/3318410/pragma-pack-effect
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// * https://www.delorie.com/djgpp/doc/dpmi/ch4.4.html
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// * https://delorie.com/djgpp/doc/dpmi/api/310100.html
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// * http://www.monstersoft.com/tutorial1/VESA_intro.html
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// * http://www.delorie.com/djgpp/doc/ug/graphics/vesa.html.en
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// * https://lhlaurini.xyz/VESA_Video_Modes
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// * https://stackoverflow.com/questions/58328264/retrieve-list-of-vesa-video-modes-from-int-10h-ax-4f00h
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// * https://github.com/execomrt/vesa2/blob/main/vbelib/vbecore.c#L262
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// * https://pdos.csail.mit.edu/6.828/2004/readings/hardware/vbe3.pdf
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#include "vesa.h"
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#include "bmp.h"
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#include "dpmi.h"
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/**
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If you want to enumerate all the possible modes to inspect, you would need
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something like this to turn the segment:offset data into array elements you can
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address in 32-bit DOS.
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uint16_t *modePtr;
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modePtr = (uint16_t*)((vbeInfo.VideoModeSegment << 4) + vbeInfo.VideoModeOffset);
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for (i = 0; i < 4; ++i) {
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printf("Available mode %d: 0x%x\n", i, modePtr[i]);
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}
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*/
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int main(void) {
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int x, y;
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FILE *bmp;
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struct BMPImage bmpImage;
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struct VESAColor colors[256];
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struct VbeInfo vbeInfo;
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struct VbeModeInfo vbeModeInfo;
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setupVESAHandling();
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vbeGetVBEInfo(&vbeInfo);
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printf("VBE Version: 0x%x\n", vbeInfo.VbeVersion);
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bmp = fopen("chkn640.bmp", "rb");
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readBMPHeader(bmp, &bmpImage);
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bmp256ColorPaletteToVESAColorPalette(&bmpImage, colors);
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// we could enumerate all the modes, but in DOSBox-X's default S3 VGA card,
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// 0x101 is 640x480x256, and that's where I'm running this. it's more correct
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// to select the mode based on examining capabilities for all available
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// modes, but...eh.
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startSVGAMode(0x101, &vbeModeInfo);
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setVESAColorPalette(colors);
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for (y = 0; y < vbeModeInfo.YResolution; ++y) {
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for (x = 0; x < vbeModeInfo.XResolution; ++x) {
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setPixel(x, vbeModeInfo.YResolution - y, fgetc(bmp));
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}
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}
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fclose(bmp);
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delay(10000);
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teardownVESAHandling();
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return 0;
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}
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133
vesa.c
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133
vesa.c
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#include <memory.h>
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#include <i86.h>
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#include <dos.h>
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#include "dpmi.h"
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#include "vesa.h"
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char far *VGA = (char*)0xA0000;
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long windowSizeBytes, bytesPerScanLine;
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void *dosmem;
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int currentWindowPosition;
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#define MAX_COLORS (256)
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void setupVESAHandling() {
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dosmem = dpmiAllocateDOSMemory(1024);
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}
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void teardownVESAHandling() {
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dpmiDeallocateDOSMemory();
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}
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void addDOSMemToRealModeRegs(struct dpmiRealModeRegs *rc) {
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rc->edi = (unsigned long)dosmem & 0xf;
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rc->es = (unsigned long)dosmem >> 4;
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}
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void vbeGetModeInfo(
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uint16_t mode,
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struct VbeModeInfo *modeInfo
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) {
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struct dpmiRealModeRegs rc={0};
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_fmemset(dosmem, 0, sizeof(struct VbeModeInfo));
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rc.eax = 0x4f01;
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rc.ecx = mode;
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addDOSMemToRealModeRegs(&rc);
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dpmiInt(0x10, &rc);
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_fmemcpy(modeInfo, dosmem, sizeof(struct VbeModeInfo));
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}
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int vbeGetVBEInfo(
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struct VbeInfo far *p
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) {
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struct dpmiRealModeRegs rc={0};
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// request VBE2 extended info
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_fmemset(p, 0, sizeof(struct VbeInfo));
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_fmemcpy(p->VbeSignature,"VBE2",4);
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_fmemcpy(dosmem, p, sizeof(struct VbeInfo));
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rc.eax = 0x4f00;
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addDOSMemToRealModeRegs(&rc);
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dpmiInt(0x10, &rc);
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_fmemcpy(p, dosmem, sizeof(struct VbeInfo));
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return 0;
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}
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void startSVGAMode(int mode, struct VbeModeInfo *vbeModeInfo) {
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/**
|
||||
* Side effects: sets some internal variables for window and scanline sizes
|
||||
*/
|
||||
union REGS regs;
|
||||
|
||||
vbeGetModeInfo(mode, vbeModeInfo);
|
||||
|
||||
windowSizeBytes = 1024L * vbeModeInfo->WinSize;
|
||||
bytesPerScanLine = vbeModeInfo->BytesPerScanLine;
|
||||
|
||||
regs.w.ax = 0x4f02;
|
||||
regs.w.bx = mode;
|
||||
int386(0x10, ®s, ®s);
|
||||
|
||||
vbeSetWindow(0, 0);
|
||||
}
|
||||
|
||||
void vbeSetWindow(int window, int position) {
|
||||
/**
|
||||
* Side effects: tracks current window position
|
||||
*/
|
||||
union REGS regs;
|
||||
|
||||
regs.w.ax = 0x4f05;
|
||||
regs.h.bh = 0;
|
||||
regs.h.bl = window;
|
||||
regs.w.dx = position;
|
||||
int386(0x10, ®s, ®s);
|
||||
|
||||
currentWindowPosition = position;
|
||||
}
|
||||
|
||||
void maybeVbeSetWindow(int window, int position) {
|
||||
if (currentWindowPosition == position) return;
|
||||
|
||||
vbeSetWindow(window, position);
|
||||
}
|
||||
|
||||
void setVESAColorPalette(
|
||||
struct VESAColor *colors
|
||||
) {
|
||||
struct dpmiRealModeRegs rc={0};
|
||||
int i;
|
||||
|
||||
_fmemcpy(dosmem, colors, MAX_COLORS * 4);
|
||||
|
||||
// prep our real mode interrupt call
|
||||
rc.eax = 0x4f09;
|
||||
rc.ebx = 0;
|
||||
rc.ecx = MAX_COLORS;
|
||||
rc.edx = 0;
|
||||
addDOSMemToRealModeRegs(&rc);
|
||||
|
||||
dpmiInt(0x10, &rc);
|
||||
}
|
||||
|
||||
void setPixel(int x, int y, int color) {
|
||||
long absolutePosition = (long)y * bytesPerScanLine + x;
|
||||
long windowPosition = absolutePosition / windowSizeBytes;
|
||||
long windowOffset = absolutePosition % windowSizeBytes;
|
||||
|
||||
/**
|
||||
* This will not shift window positions unless needed.
|
||||
*/
|
||||
maybeVbeSetWindow(0, windowPosition);
|
||||
|
||||
VGA[windowOffset] = color;
|
||||
}
|
||||
57
vesa.h
Normal file
57
vesa.h
Normal file
@ -0,0 +1,57 @@
|
||||
#ifndef __VESA_H__
|
||||
#define __VESA_H__
|
||||
|
||||
#include <sys/types.h>
|
||||
|
||||
#pragma pack(push,1)
|
||||
struct VbeInfo {
|
||||
char VbeSignature[4];
|
||||
uint16_t VbeVersion;
|
||||
uint32_t OemStringPtr;
|
||||
uint32_t Capabilities;
|
||||
|
||||
uint16_t VideoModeOffset;
|
||||
uint16_t VideoModeSegment;
|
||||
|
||||
uint16_t TotalMemory;
|
||||
|
||||
int OemSoftwareRev;
|
||||
char far *OemVendorNamePtr;
|
||||
char far *OemProductNamePtr;
|
||||
char far *OenProductRevPtr;
|
||||
char Reserved[222];
|
||||
char OemData[256];
|
||||
};
|
||||
|
||||
struct VbeModeInfo {
|
||||
uint16_t ModeAttributes;
|
||||
uint8_t WinAAttributes;
|
||||
uint8_t WinBAttributes;
|
||||
uint16_t WinGranularity;
|
||||
uint16_t WinSize;
|
||||
uint16_t WinASegment;
|
||||
uint16_t WinBSegment;
|
||||
void *WindowFunction;
|
||||
uint16_t BytesPerScanLine;
|
||||
uint16_t XResolution;
|
||||
uint16_t YResolution;
|
||||
uint8_t XCharSize;
|
||||
uint8_t YCharSize;
|
||||
uint8_t NumberOfPlanes;
|
||||
uint8_t BitsPerPixel;
|
||||
uint8_t NumberOfBanks;
|
||||
uint8_t MemoryModel;
|
||||
uint8_t BankSize;
|
||||
uint8_t NumberOfImagePages;
|
||||
char more[500];
|
||||
};
|
||||
|
||||
struct VESAColor {
|
||||
uint8_t blue;
|
||||
uint8_t green;
|
||||
uint8_t red;
|
||||
uint8_t _a;
|
||||
};
|
||||
#pragma pack(pop)
|
||||
|
||||
#endif
|
||||
108
vga.asm
108
vga.asm
@ -4,7 +4,6 @@ PUBLIC _fillScreen
|
||||
PUBLIC _latchCopyCube
|
||||
PUBLIC _drawColorCube
|
||||
PUBLIC _writeCube
|
||||
PUBLIC _paramTest
|
||||
PUBLIC _keyboardPressed
|
||||
PUBLIC keyboardHandler_
|
||||
|
||||
@ -39,6 +38,7 @@ keyboardHandler_:
|
||||
push eax
|
||||
push ebx
|
||||
|
||||
; put scancode into bl
|
||||
in al, 0x60
|
||||
mov bl, al
|
||||
|
||||
@ -50,6 +50,7 @@ keyboardHandler_:
|
||||
xchg ah, al
|
||||
out 0x61, al
|
||||
|
||||
; a key is pressed if the topmost bit of the scancode is 0
|
||||
and bl,0x80
|
||||
jne _keyboardHandler_notKeydown
|
||||
|
||||
@ -62,8 +63,10 @@ _keyboardHandler_notKeydown:
|
||||
pop ebx
|
||||
pop eax
|
||||
sti
|
||||
; return from the interrupt in a way that preserves the calling stack
|
||||
iretd
|
||||
|
||||
|
||||
_enableUnchainedVGAMode:
|
||||
mov ax,0x0013;
|
||||
int 0x10
|
||||
@ -85,12 +88,14 @@ _enableUnchainedVGAMode:
|
||||
|
||||
ret
|
||||
|
||||
|
||||
_enableTextMode:
|
||||
mov ah,0h
|
||||
mov al,DISPLAY_MODE_TEXT
|
||||
int 10h
|
||||
ret
|
||||
|
||||
|
||||
_fillScreen:
|
||||
push ebp
|
||||
mov ebp, esp
|
||||
@ -98,34 +103,45 @@ _fillScreen:
|
||||
; set all bitplanes
|
||||
mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
|
||||
mov al, 0x02
|
||||
mov ah, 0fh
|
||||
mov ah, 0x0f
|
||||
out dx, ax
|
||||
|
||||
push ebx
|
||||
push ecx
|
||||
push edx
|
||||
sub eax,eax
|
||||
mov al, [ebp+8] ; requested color
|
||||
|
||||
mov cx, 16000 ; loop index
|
||||
mov ebx, 0xa0000
|
||||
; we can write a long at a time and let the bus
|
||||
; and BIU work out the details. on a 16-bit ISA
|
||||
; bus with a 16-bit VGA card, this will be faster
|
||||
; than byte writes
|
||||
sub edx,edx
|
||||
add dl,al
|
||||
shl edx,8
|
||||
add dl,al
|
||||
shl edx,8
|
||||
add dl,al
|
||||
shl edx,8
|
||||
add dl,al
|
||||
|
||||
; with all planes selected we only need to fill 16000 bytes of data
|
||||
; and we're filling them four bytes at a time
|
||||
mov cx, 4000
|
||||
mov ebx, 0xA0000 ; VGA base address
|
||||
_fillScreen_loop:
|
||||
mov BYTE PTR [ebx], al
|
||||
inc ebx
|
||||
mov DWORD PTR [ebx], edx
|
||||
add ebx,4
|
||||
loop _fillScreen_loop
|
||||
pop edx
|
||||
pop ecx
|
||||
pop ebx
|
||||
|
||||
mov esp,ebp
|
||||
pop ebp
|
||||
|
||||
ret
|
||||
|
||||
_paramTest:
|
||||
push ebp
|
||||
mov ebp,esp
|
||||
|
||||
mov eax,0
|
||||
mov al, BYTE PTR [ebp+8]
|
||||
|
||||
mov esp,ebp
|
||||
pop ebp
|
||||
ret
|
||||
|
||||
|
||||
_drawColorCube:
|
||||
push ebp
|
||||
@ -165,6 +181,7 @@ _drawColorCube:
|
||||
_drawColorCube_yLoop:
|
||||
mov [ebp-4],cx
|
||||
|
||||
; put the VGA write offset into eax
|
||||
mov eax,[ebp-4]
|
||||
dec eax
|
||||
mov bl,80
|
||||
@ -174,7 +191,7 @@ _drawColorCube_yLoop:
|
||||
|
||||
mov cx, 4
|
||||
_drawColorCube_xLoop:
|
||||
mov [eax],bh ; write color
|
||||
mov [eax],bh ; write color four bytes at a time
|
||||
inc eax
|
||||
|
||||
loop _drawColorCube_xLoop
|
||||
@ -190,15 +207,15 @@ _drawColorCube_xLoop:
|
||||
ret
|
||||
|
||||
|
||||
|
||||
|
||||
_writeCube:
|
||||
push ebp
|
||||
mov ebp,esp
|
||||
; we need a y variable
|
||||
sub esp,4
|
||||
; and a current color
|
||||
sub esp,4
|
||||
|
||||
push ebx
|
||||
push ecx
|
||||
push edx
|
||||
|
||||
; [ebp+8] is x offset
|
||||
; [ebp+12] is data rotate
|
||||
@ -222,57 +239,66 @@ _writeCube:
|
||||
mov ah, [ebp+20]
|
||||
out dx, ax
|
||||
|
||||
mov DWORD PTR [ebp-8],0
|
||||
mov DWORD PTR [ebp-4],16
|
||||
mov cx,[ebp-4]
|
||||
|
||||
_writeCube_yLoop:
|
||||
mov [ebp-4],cx
|
||||
|
||||
; determine the offset within VGA memory to write this line to
|
||||
; and put it in eax
|
||||
mov eax,[ebp-4]
|
||||
dec eax
|
||||
mov bl,80
|
||||
mul bl
|
||||
add eax,0xa0000
|
||||
add eax,0xA0000
|
||||
|
||||
; 16 pixels across
|
||||
mov cx,16
|
||||
_writeCube_xLoop:
|
||||
; get the current plane
|
||||
push eax
|
||||
; get the plane to write to in bl
|
||||
push ecx
|
||||
dec cl
|
||||
and cl,0x03
|
||||
|
||||
jne _writeCube_dontAdvanceVGA
|
||||
inc eax
|
||||
_writeCube_dontAdvanceVGA:
|
||||
|
||||
dec ecx
|
||||
and ecx,0x03
|
||||
mov bl,1
|
||||
sal bl,cl
|
||||
shl bl,cl
|
||||
pop ecx
|
||||
|
||||
push eax
|
||||
; write to one plane
|
||||
mov dx, VGA_SEQUENCE_CONTROLLER_INDEX
|
||||
mov al, VGA_SEQUENCE_CONTROLLER_MAP_MASK_MODE
|
||||
mov ah, bl
|
||||
out dx, ax
|
||||
|
||||
; select color to write into bl
|
||||
mov ax,[ebp-4]
|
||||
dec ax
|
||||
mov bl,16
|
||||
mul bl
|
||||
add al,cl
|
||||
mov bl,al
|
||||
pop eax
|
||||
|
||||
;mov ebx,[ebp+8]
|
||||
|
||||
push edx
|
||||
push ecx
|
||||
mov ecx,[ebp+8]
|
||||
mov bl,[ebp-8]
|
||||
; select the correct pixel offset (x / 4) and write the color
|
||||
dec ecx
|
||||
shr ecx,2
|
||||
add ecx,[ebp+8]
|
||||
mov BYTE PTR [eax+ecx],bl
|
||||
inc bl
|
||||
mov [ebp-8],bl
|
||||
pop ecx
|
||||
pop edx
|
||||
|
||||
loop _writeCube_xLoop
|
||||
|
||||
mov cx,[ebp-4]
|
||||
loop _writeCube_yLoop
|
||||
|
||||
pop edx
|
||||
pop ecx
|
||||
pop ebx
|
||||
|
||||
mov esp,ebp
|
||||
pop ebp
|
||||
ret
|
||||
@ -359,6 +385,8 @@ _latchCopyCube_xLoop:
|
||||
; loop until y is 0
|
||||
loop _latchCopyCube_yLoop
|
||||
|
||||
_done:
|
||||
|
||||
; put things back
|
||||
pop ebx
|
||||
pop edx
|
||||
|
||||
Loading…
Reference in New Issue
Block a user