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Revert set_pixel

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This commit is contained in:
Ryan Kennedy 2020-03-22 14:11:35 -05:00
parent 01d75b971a
commit 9be03f1190
1 changed files with 18 additions and 13 deletions
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31
src/writers/graphics_640x480x16.rs
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@ -2,6 +2,7 @@ use crate::{
colors::{Color16Bit, DEFAULT_PALETTE},
vga::{PlaneMask, Vga, VideoMode, VGA},
};
use core::convert::TryInto;
use spinning_top::SpinlockGuard;
const WIDTH: usize = 640;
@ -50,20 +51,24 @@ impl Graphics640x480x16 {
let (mut vga, frame_buffer) = self.get_frame_buffer();
let offset = x / 8 + (WIDTH / 8) * y;
// Write to all 4 planes
vga.set_plane_mask(PlaneMask::ALL_PLANES);
// Store the current value for masking.
let x = x & 7;
let mask = 0x80 >> (x & 7);
let mut plane_mask = 0x01;
// Set the bits we want set/reset to the color
vga.set_graphics_set_reset(color);
// Enable set/reset for all planes
vga.set_graphics_enable_set_reset(PlaneMask::ALL_PLANES);
unsafe {
// In write mode 0, when enable set/reset is turned on, cpu data
// is replaced with the data from the set/reset register. Since
// we're using set/reset for all 4 planes, it doesn't matter what value
// we write to the memory address.
frame_buffer.add(offset).write(0x0);
for plane in 0u8..4u8 {
vga.set_read_plane(plane.try_into().unwrap());
vga.set_plane_mask(plane.try_into().unwrap());
let current_value = unsafe { frame_buffer.add(offset).read_volatile() };
let new_value = if plane_mask & color as u8 != 0 {
current_value | mask
} else {
current_value & !mask
};
unsafe {
frame_buffer.add(offset).write_volatile(new_value);
}
plane_mask <<= 1;
}
}