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vid_ega: Hoist out + name chip register flags in renderers; Tweak graphics char writing loop

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This commit is contained in:
Ben Russell
2023-03-23 20:02:08 +13:00
parent 240ecdfe5f
commit 935d49da6c
1 changed files with 23 additions and 15 deletions
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38
src/video/vid_ega_render.c
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@@ -116,10 +116,16 @@ ega_render_text(ega_t *ega)
ega->lastline_draw = ega->displine;
if (ega->fullchange) {
const bool doublewidth = ((ega->seqregs[1] & 8) != 0);
const bool attrblink = ((ega->attrregs[0x10] & 8) != 0);
const bool attrlinechars = (ega->attrregs[0x10] & 4);
const bool crtcreset = ((ega->crtc[0x17] & 0x80) == 0);
const bool seq9dot = ((ega->seqregs[1] & 1) == 0);
const int dwshift = doublewidth ? 1 : 0;
const int dotwidth = 1 << dwshift;
const int charwidth = dotwidth*(seq9dot ? 9 : 8);
const bool blinked = ega->blink & 0x10;
uint32_t *p = &buffer32->line[ega->displine + ega->y_add][ega->x_add];
const int dwshift = (ega->seqregs[1] & 8) ? 1 : 0;
const int dotwidth = 1<<dwshift;
const int charwidth = dotwidth*((ega->seqregs[1] & 1) ? 8 : 9);
for (int x = 0; x < (ega->hdisp + ega->scrollcache); x += charwidth) {
uint32_t addr = ega->remap_func(ega, ega->ma) & ega->vrammask;
@@ -127,7 +133,7 @@ ega_render_text(ega_t *ega)
int drawcursor = ((ega->ma == ega->ca) && ega->con && ega->cursoron);
uint32_t chr, attr;
if (ega->crtc[0x17] & 0x80) {
if (!crtcreset) {
chr = ega->vram[addr];
attr = ega->vram[addr + 1];
} else
@@ -147,16 +153,16 @@ ega_render_text(ega_t *ega)
fg = ega->pallook[ega->egapal[attr & 0x0f]];
bg = ega->pallook[ega->egapal[attr >> 4]];
if ((attr & 0x80) && ega->attrregs[0x10] & 8) {
if ((attr & 0x80) && attrblink) {
bg = ega->pallook[ega->egapal[(attr >> 4) & 7]];
if (ega->blink & 0x10)
if (blinked)
fg = bg;
}
}
uint32_t dat = ega->vram[charaddr + (ega->sc << 2)];
dat <<= 1;
if ((chr & ~0x1F) == 0xC0 && (ega->attrregs[0x10] & 4))
if ((chr & ~0x1F) == 0xC0 && attrlinechars)
dat |= (dat >> 1) & 1;
for (int xx = 0; xx < charwidth; xx++)
@@ -175,22 +181,24 @@ ega_render_graphics(ega_t *ega)
if ((ega->displine + ega->y_add) < 0)
return;
uint32_t *p = &buffer32->line[ega->displine + ega->y_add][ega->x_add];
if (ega->firstline_draw == 2000)
ega->firstline_draw = ega->displine;
ega->lastline_draw = ega->displine;
const bool doublewidth = ((ega->seqregs[1] & 8) != 0);
const bool cga2bpp = ((ega->gdcreg[5] & 0x20) != 0);
const int dotwidth = (doublewidth ? 2 : 1);
const bool crtcreset = ((ega->crtc[0x17] & 0x80) == 0);
const bool seqoddeven = ((ega->seqregs[1] & 4) != 0);
uint32_t *p = &buffer32->line[ega->displine + ega->y_add][ega->x_add];
const int dwshift = doublewidth ? 1 : 0;
const int dotwidth = 1 << dwshift;
const int charwidth = dotwidth*8;
int secondcclk = 0;
for (int x = 0; x <= (ega->hdisp + ega->scrollcache); x += charwidth) {
uint32_t addr = ega->remap_func(ega, ega->ma) & ega->vrammask;
uint8_t edat[4];
if (ega->seqregs[1] & 4) {
if (seqoddeven) {
// FIXME: Verify the behaviour of planes 1,3 on actual hardware
edat[0] = ega->vram[(addr | 0) ^ secondcclk];
edat[1] = ega->vram[(addr | 1) ^ secondcclk];
@@ -217,10 +225,10 @@ ega_render_graphics(ega_t *ega)
edat[3] = dat3;
}
if (ega->crtc[0x17] & 0x80) {
for (int i = 0; i < 4; i++) {
const int outoffs = i*(dotwidth<<1);
const int inshift = 6 - (i<<1);
if (!crtcreset) {
for (int i = 0; i < 8; i += 2) {
const int outoffs = i << dwshift;
const int inshift = 6 - i;
uint8_t dat = (edatlookup[(edat[0] >> inshift) & 3][(edat[1] >> inshift) & 3] )
| (edatlookup[(edat[2] >> inshift) & 3][(edat[3] >> inshift) & 3] << 2);
uint32_t p0 = ega->pallook[ega->egapal[(dat >> 4) & ega->plane_mask]];