From 9844cbc2459cc33d18ae17253e431547e5504579 Mon Sep 17 00:00:00 2001 From: GreaseMonkey Date: Tue, 23 Jan 2024 16:02:32 +1300 Subject: [PATCH] Add 8-dot hscroll compensation to EGA graphics modes This is in lieu of whatever the correct emulation would be (as per the text modes). Somehow I forgot to add this when reworking the fine scroll implementations. --- src/video/vid_ega_render.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/video/vid_ega_render.c b/src/video/vid_ega_render.c index 98905e0c8..0cb1216ad 100644 --- a/src/video/vid_ega_render.c +++ b/src/video/vid_ega_render.c @@ -199,6 +199,7 @@ ega_render_graphics(ega_t *ega) const bool attrblink = ((ega->attrregs[0x10] & 8) != 0); const bool blinked = ega->blink & 0x10; const bool crtcreset = ((ega->crtc[0x17] & 0x80) == 0); + const bool seq9dot = ((ega->seqregs[1] & 1) == 0); const bool seqoddeven = ((ega->seqregs[1] & 4) != 0); const uint8_t blinkmask = (attrblink && blinked ? 0x8 : 0x0); uint32_t *p = &buffer32->line[ega->displine + ega->y_add][ega->x_add]; @@ -206,6 +207,15 @@ ega_render_graphics(ega_t *ega) const int dotwidth = 1 << dwshift; const int charwidth = dotwidth * 8; int secondcclk = 0; + + /* Compensate for 8dot scroll */ + if (!seq9dot) { + for (int x = 0; x < dotwidth; x++) { + p[x] = ega->overscan_color; + } + p += dotwidth; + } + for (int x = 0; x <= (ega->hdisp + ega->scrollcache); x += charwidth) { uint32_t addr = ega->remap_func(ega, ega->ma) & ega->vrammask;