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Some fixes for the VGA mode 0x13 (issue #188 and discussion #108).

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- Shift start address by 2 in update() code and mem_write().
- Added split screen support for this mode.
- Some code cleanups.
This commit is contained in:
Volker Ruppert 2023-12-23 21:37:08 +01:00
parent b4effb58af
commit e3eb603ad4
1 changed files with 62 additions and 38 deletions
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100
bochs/iodev/display/vgacore.cc
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@ -1379,8 +1379,6 @@ void bx_vgacore_c::update(void)
// 2: output data 8 bits at a time from the 4 bit planes
// (mode 13 and variants like modeX)
// if (BX_VGA_THIS s.vga_mem_updated==0 || BX_VGA_THIS s.attribute_ctrl.video_enabled == 0)
if (BX_VGA_THIS s.graphics_ctrl.graphics_alpha) {
// Graphics mode
Bit8u color;
@ -1511,22 +1509,32 @@ void bx_vgacore_c::update(void)
case 3: // FIXME: is this really the same ???
if (BX_VGA_THIS s.CRTC.reg[0x14] & 0x40) { // DW set: doubleword mode
unsigned long pixely, pixelx, plane;
unsigned long plane;
if (BX_VGA_THIS s.misc_output.select_high_bank != 1)
BX_PANIC(("update: select_high_bank != 1"));
start_addr <<= 2;
for (yc=0, yti=0; yc<iHeight; yc+=Y_TILESIZE, yti++) {
for (xc=0, xti=0; xc<iWidth; xc+=X_TILESIZE, xti++) {
if (GET_TILE_UPDATED (xti, yti)) {
for (r=0; r<Y_TILESIZE; r++) {
pixely = yc + r;
if (BX_VGA_THIS s.y_doublescan) pixely >>= 1;
if ((yc + r) >= BX_VGA_THIS s.line_compare) {
y = (yc - BX_VGA_THIS s.line_compare) + r;
} else {
y = yc + r;
}
if (BX_VGA_THIS s.y_doublescan) y >>= 1;
for (c=0; c<X_TILESIZE; c++) {
pixelx = (xc + c) >> 1;
plane = (pixelx % 4);
byte_offset = start_addr + (plane * 65536) +
(pixely * BX_VGA_THIS s.line_offset) + (pixelx & ~0x03);
x = (xc + c) >> 1;
plane = (x % 4);
if ((yc + r) >= BX_VGA_THIS s.line_compare) {
byte_offset = (plane << 16) +
(y * BX_VGA_THIS s.line_offset) + (x & ~0x03);
} else {
byte_offset = start_addr + (plane << 16) +
(y * BX_VGA_THIS s.line_offset) + (x & ~0x03);
}
color = BX_VGA_THIS s.memory[byte_offset];
BX_VGA_THIS s.tile[r*X_TILESIZE + c] = color;
}
@ -1537,29 +1545,29 @@ void bx_vgacore_c::update(void)
}
}
} else if (BX_VGA_THIS s.CRTC.reg[0x17] & 0x40) { // B/W set: byte mode, modeX
unsigned long pixely, pixelx, plane;
unsigned long plane;
for (yc=0, yti=0; yc<iHeight; yc+=Y_TILESIZE, yti++) {
for (xc=0, xti=0; xc<iWidth; xc+=X_TILESIZE, xti++) {
if (GET_TILE_UPDATED (xti, yti)) {
for (r=0; r<Y_TILESIZE; r++) {
if ((yc + r) >= BX_VGA_THIS s.line_compare) {
pixely = (yc - BX_VGA_THIS s.line_compare) + r;
y = (yc - BX_VGA_THIS s.line_compare) + r;
} else {
pixely = yc + r;
y = yc + r;
}
if (BX_VGA_THIS s.y_doublescan) pixely >>= 1;
if (BX_VGA_THIS s.y_doublescan) y >>= 1;
for (c=0; c<X_TILESIZE; c++) {
pixelx = (xc + c) >> 1;
plane = (pixelx % 4);
x = (xc + c) >> 1;
plane = (x % 4);
if ((yc + r) >= BX_VGA_THIS s.line_compare) {
byte_offset = (plane * 65536) +
(pixely * BX_VGA_THIS s.line_offset)
+ (pixelx >> 2);
byte_offset = (plane << 16) +
(y * BX_VGA_THIS s.line_offset)
+ (x >> 2);
} else {
byte_offset = start_addr + (plane * 65536) +
(pixely * BX_VGA_THIS s.line_offset)
+ (pixelx >> 2);
byte_offset = start_addr + (plane << 16) +
(y * BX_VGA_THIS s.line_offset)
+ (x >> 2);
}
color = BX_VGA_THIS s.memory[byte_offset];
BX_VGA_THIS s.tile[r*X_TILESIZE + c] = color;
@ -1571,20 +1579,20 @@ void bx_vgacore_c::update(void)
}
}
} else { // word mode
unsigned long pixely, pixelx, plane;
unsigned long plane;
for (yc=0, yti=0; yc<iHeight; yc+=Y_TILESIZE, yti++) {
for (xc=0, xti=0; xc<iWidth; xc+=X_TILESIZE, xti++) {
if (GET_TILE_UPDATED (xti, yti)) {
for (r=0; r<Y_TILESIZE; r++) {
pixely = yc + r;
if (BX_VGA_THIS s.y_doublescan) pixely >>= 1;
y = yc + r;
if (BX_VGA_THIS s.y_doublescan) y >>= 1;
for (c=0; c<X_TILESIZE; c++) {
pixelx = (xc + c) >> 1;
plane = (pixelx % 4);
byte_offset = (plane * 65536) +
(pixely * BX_VGA_THIS s.line_offset)
+ ((pixelx >> 1) & ~0x01);
x = (xc + c) >> 1;
plane = (x % 4);
byte_offset = (plane << 16) +
(y * BX_VGA_THIS s.line_offset)
+ ((x >> 1) & ~0x01);
color = BX_VGA_THIS s.memory[start_addr + byte_offset];
BX_VGA_THIS s.tile[r*X_TILESIZE + c] = color;
}
@ -1898,18 +1906,34 @@ void bx_vgacore_c::mem_write(bx_phy_address addr, Bit8u value)
if (BX_VGA_THIS s.sequencer.chain_four) {
unsigned x_tileno, y_tileno;
if (BX_VGA_THIS s.CRTC.reg[0x14] & 0x40) {
start_addr <<= 2;
}
// 320 x 200 256 color mode: chained pixel representation
BX_VGA_THIS s.memory[(offset & ~0x03) + (offset % 4)*65536] = value;
if (BX_VGA_THIS s.line_offset > 0) {
offset -= start_addr;
x_tileno = (offset % BX_VGA_THIS s.line_offset) / (X_TILESIZE/2);
if (BX_VGA_THIS s.y_doublescan) {
y_tileno = (offset / BX_VGA_THIS s.line_offset) / (Y_TILESIZE/2);
} else {
y_tileno = (offset / BX_VGA_THIS s.line_offset) / Y_TILESIZE;
if (BX_VGA_THIS s.line_compare < BX_VGA_THIS s.vertical_display_end) {
if (BX_VGA_THIS s.line_offset > 0) {
x_tileno = (offset % BX_VGA_THIS s.line_offset) / (X_TILESIZE / 2);
if (BX_VGA_THIS s.y_doublescan) {
y_tileno = ((offset / BX_VGA_THIS s.line_offset) + BX_VGA_THIS s.line_compare + 1) / Y_TILESIZE;
} else {
y_tileno = ((offset / BX_VGA_THIS s.line_offset) + BX_VGA_THIS s.line_compare + 1) / (Y_TILESIZE / 2);
}
SET_TILE_UPDATED(BX_VGA_THIS, x_tileno, y_tileno, 1);
}
}
if (BX_VGA_THIS s.line_offset > 0) {
if (offset >= start_addr) {
offset -= start_addr;
x_tileno = (offset % BX_VGA_THIS s.line_offset) / (X_TILESIZE / 2);
if (BX_VGA_THIS s.y_doublescan) {
y_tileno = (offset / BX_VGA_THIS s.line_offset) / (Y_TILESIZE / 2);
} else {
y_tileno = (offset / BX_VGA_THIS s.line_offset) / Y_TILESIZE;
}
BX_VGA_THIS s.vga_mem_updated = 1;
SET_TILE_UPDATED(BX_VGA_THIS, x_tileno, y_tileno, 1);
}
BX_VGA_THIS s.vga_mem_updated = 1;
SET_TILE_UPDATED(BX_VGA_THIS, x_tileno, y_tileno, 1);
}
return;
}