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Bare metal VGA: enable bright background colors, disable blinking (#603)

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Co-authored-by: tkchia <tkchia-cosmo@gmx.com>
This commit is contained in:
tkchia 2022-09-09 19:35:16 +08:00 • committed by GitHub
parent f68151c010
commit 1db76c288e
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 64 additions and 9 deletions
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31
libc/vga/tty.c
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@ -263,8 +263,10 @@ static uint8_t TtyGetVgaAttr(struct Tty *tty)
uint8_t attr = tty->fg | tty->bg << 4;
if ((tty->pr & kTtyBold) != 0)
attr |= 0x08;
#ifdef VGA_USE_BLINK
if ((tty->pr & kTtyBlink) != 0)
attr |= 0x80;
#endif
return attr;
}
@ -637,14 +639,25 @@ static void TtyCsiN(struct Tty *tty) {
/**
* Map the given (R, G, B) triplet to one of the 16 basic foreground colors
* or one of the 8 background colors.
* or one of the 8 (or 16) background colors.
*
* @see VGA_USE_BLINK macro (libc/vga/vga.internal.h)
* @see drivers/tty/vt/vt.c in Linux 5.9.14 source code
*/
static uint8_t TtyMapTrueColor(uint8_t r, uint8_t g, uint8_t b, bool as_fg)
{
uint8_t hue = 0;
if (as_fg) {
#ifdef VGA_USE_BLINK
if (!as_fg) {
if (r >= 128)
hue |= 4;
if (g >= 128)
hue |= 2;
if (b >= 128)
hue |= 1;
} else
#endif
{
uint8_t max = MAX(MAX(r, g), b);
if (r > max / 2)
hue |= 4;
@ -656,13 +669,6 @@ static uint8_t TtyMapTrueColor(uint8_t r, uint8_t g, uint8_t b, bool as_fg)
hue = 8;
else if (max > 0xaa)
hue |= 8;
} else {
if (r >= 128)
hue |= 4;
if (g >= 128)
hue |= 2;
if (b >= 128)
hue |= 1;
}
return hue;
}
@ -816,6 +822,13 @@ static void TtySelectGraphicsRendition(struct Tty *tty) {
break;
case 100 ... 107:
code[0] -= 100 - 40;
#ifndef VGA_USE_BLINK
/*
* If blinking is not enabled in VGA text mode, then we can
* use bright background colors.
*/
code[0] += 8;
#endif
/* fallthrough */
case 40 ... 47:
tty->bg = code[0] - 40;