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add "fb" module for framebuffer control

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This commit is contained in:
Josh Holtrop 2020-10-19 22:09:33 -04:00
parent 67b90a482f
commit bb495eceec
3 changed files with 40 additions and 25 deletions
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30
src/fb.c Normal file
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@ -0,0 +1,30 @@
#include "fb.h"
static uint32_t * fb;
static uint32_t fb_width;
static uint32_t fb_height;
static uint32_t fb_pitch;
void fb_init(uint32_t * addr, uint32_t width, uint32_t height, uint32_t pitch)
{
fb = addr;
fb_width = width;
fb_height = height;
fb_pitch = pitch;
for (uint32_t row = 0u; row < fb_height; row++)
{
for (uint32_t col = 0u; col < fb_width; col++)
{
uint32_t er = (col * fb_height) / fb_width;
int32_t dr = (int32_t)row - (int32_t)er;
if (dr < 0)
{
dr = -dr;
}
uint8_t r = 255u - ((uint32_t)dr * 256u / fb_height);
uint8_t g = col * 256u / fb_width;
uint8_t b = row * 256u / fb_height;
fb[fb_pitch * row / 4u + col] = (r << 16u) | (g << 8u) | b;
}
}
}

8
src/fb.h Normal file
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@ -0,0 +1,8 @@
#ifndef FB_H
#define FB_H
#include <stdint.h>
void fb_init(uint32_t * addr, uint32_t width, uint32_t height, uint32_t pitch);
#endif

27
src/kernel_main.c
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@ -1,9 +1,5 @@
#include <stdint.h>
uint32_t * fb;
uint32_t pitch;
uint32_t width;
uint32_t height;
#include "fb.h"
static uint32_t * process_mbinfo_tag(uint32_t * mbinfo)
{
@ -15,10 +11,7 @@ static uint32_t * process_mbinfo_tag(uint32_t * mbinfo)
return 0u;
case 8u:
fb = (uint32_t *)mbinfo[2];
pitch = mbinfo[4];
width = mbinfo[5];
height = mbinfo[6];
fb_init((uint32_t *)mbinfo[2], mbinfo[5], mbinfo[6], mbinfo[4]);
break;
}
return (uint32_t *)(((uint32_t)mbinfo + size + 7u) & 0xFFFFFFF8u);
@ -37,20 +30,4 @@ static void process_mbinfo(uint32_t * mbinfo)
void kernel_main(uint32_t * mbinfo)
{
process_mbinfo(mbinfo);
for (uint32_t row = 0u; row < height; row++)
{
for (uint32_t col = 0u; col < width; col++)
{
uint32_t er = (col * height) / width;
int32_t dr = (int32_t)row - (int32_t)er;
if (dr < 0)
{
dr = -dr;
}
uint8_t r = 255u - ((uint32_t)dr * 256u / height);
uint8_t g = col * 256u / width;
uint8_t b = row * 256u / height;
fb[pitch * row / 4u + col] = (r << 16u) | (g << 8u) | b;
}
}
}