On Mon, 2 Mar 2026, Chad Jablonski wrote:
Implement flushing the 128-bit HOST_DATA accumulator to VRAM to enable
text rendering in X. Supports all datatypes (monochrome frgd/bkgd,
monochrome frgd, and color), however monochrome frgd support is
partial and does not properly handle transparency/leave-alone.
The flush is broken up into two steps. First, if necessary, expansion of the
monochrome bits to the destination color depth. Then the expanded pixels
are sent to the ati_2d_do_blt one scanline at a time. ati_2d_do_blt then
clips and performs the blit.
Signed-off-by: Chad Jablonski <[email protected]>
Reviewed-by: BALATON Zoltan <[email protected]>
Also tested that it works with MorphOS that was known to need it for some
font rendering so this fixes Xorg and MorphOS. It is now fully reviewed,
but I can't send pull requests so is there anybody collecting patches for
hw/display and will send a pull before the freeze? I may have one more
patch to send before the freeze but otherwise this series is all we would
like to include for ati-vga in the coming release.
Thank you,
BALATON Zoltan
---
hw/display/ati.c | 6 +-
hw/display/ati_2d.c | 131 +++++++++++++++++++++++++++++++++++++++++-
hw/display/ati_int.h | 3 +
hw/display/ati_regs.h | 4 ++
4 files changed, 138 insertions(+), 6 deletions(-)
diff --git a/hw/display/ati.c b/hw/display/ati.c
index fa31401ba6..c93ef64525 100644
--- a/hw/display/ati.c
+++ b/hw/display/ati.c
@@ -1038,11 +1038,9 @@ static void ati_mm_write(void *opaque, hwaddr addr,
}
s->host_data.acc[s->host_data.next++] = data;
if (addr == HOST_DATA_LAST) {
- qemu_log_mask(LOG_UNIMP, "HOST_DATA finish not yet implemented\n");
- s->host_data.next = 0;
+ ati_host_data_finish(s);
} else if (s->host_data.next >= 4) {
- qemu_log_mask(LOG_UNIMP, "HOST_DATA flush not yet implemented\n");
- s->host_data.next = 0;
+ ati_host_data_flush(s);
}
break;
default:
diff --git a/hw/display/ati_2d.c b/hw/display/ati_2d.c
index e240093f12..549a85dd3c 100644
--- a/hw/display/ati_2d.c
+++ b/hw/display/ati_2d.c
@@ -47,6 +47,7 @@ static int ati_bpp_from_datatype(const ATIVGAState *s)
typedef struct {
int bpp;
uint32_t rop3;
+ bool host_data_active;
bool left_to_right;
bool top_to_bottom;
uint32_t frgd_clr;
@@ -85,6 +86,7 @@ static void setup_2d_blt_ctx(const ATIVGAState *s, ATI2DCtx
*ctx)
{
ctx->bpp = ati_bpp_from_datatype(s);
ctx->rop3 = s->regs.dp_mix & GMC_ROP3_MASK;
+ ctx->host_data_active = s->host_data.active;
ctx->left_to_right = s->regs.dp_cntl & DST_X_LEFT_TO_RIGHT;
ctx->top_to_bottom = s->regs.dp_cntl & DST_Y_TOP_TO_BOTTOM;
ctx->frgd_clr = s->regs.dp_brush_frgd_clr;
@@ -181,10 +183,10 @@ static bool ati_2d_do_blt(ATI2DCtx *ctx, uint8_t
use_pixman)
return false;
}
int src_stride_words = ctx->src_stride / sizeof(uint32_t);
- if (vis_src.x > 0x3fff || vis_src.y > 0x3fff
+ if (!ctx->host_data_active && (vis_src.x > 0x3fff || vis_src.y > 0x3fff
|| ctx->src_bits >= ctx->vram_end
|| ctx->src_bits + vis_src.x + (vis_src.y + vis_dst.height)
- * ctx->src_stride >= ctx->vram_end) {
+ * ctx->src_stride >= ctx->vram_end)) {
qemu_log_mask(LOG_UNIMP, "blt outside vram not implemented\n");
return false;
}
@@ -298,8 +300,133 @@ static bool ati_2d_do_blt(ATI2DCtx *ctx, uint8_t
use_pixman)
void ati_2d_blt(ATIVGAState *s)
{
ATI2DCtx ctx;
+ uint32_t src_source = s->regs.dp_mix & DP_SRC_SOURCE;
+
+ /* Finish any active HOST_DATA blits before starting a new blit */
+ ati_host_data_finish(s);
+
+ if (src_source == DP_SRC_HOST || src_source == DP_SRC_HOST_BYTEALIGN) {
+ /* Begin a HOST_DATA blit */
+ s->host_data.active = true;
+ s->host_data.next = 0;
+ s->host_data.col = 0;
+ s->host_data.row = 0;
+ return;
+ }
setup_2d_blt_ctx(s, &ctx);
if (ati_2d_do_blt(&ctx, s->use_pixman)) {
ati_set_dirty(&s->vga, &ctx);
}
}
+
+bool ati_host_data_flush(ATIVGAState *s)
+{
+ ATI2DCtx ctx, chunk;
+ uint32_t fg = s->regs.dp_src_frgd_clr;
+ uint32_t bg = s->regs.dp_src_bkgd_clr;
+ unsigned bypp, pix_count, row, col, idx;
+ uint8_t pix_buf[ATI_HOST_DATA_ACC_BITS * sizeof(uint32_t)];
+ uint32_t byte_pix_order = s->regs.dp_datatype & DP_BYTE_PIX_ORDER;
+ uint32_t src_source = s->regs.dp_mix & DP_SRC_SOURCE;
+ uint32_t src_datatype = s->regs.dp_datatype & DP_SRC_DATATYPE;
+
+ if (!s->host_data.active) {
+ return false;
+ }
+ if (src_source != DP_SRC_HOST) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "host_data_blt: unsupported src_source %x\n",
src_source);
+ return false;
+ }
+ if (src_datatype != SRC_MONO_FRGD_BKGD && src_datatype != SRC_MONO_FRGD &&
+ src_datatype != SRC_COLOR) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "host_data_blt: undefined src_datatype %x\n",
+ src_datatype);
+ return false;
+ }
+
+ setup_2d_blt_ctx(s, &ctx);
+
+ if (!ctx.left_to_right || !ctx.top_to_bottom) {
+ qemu_log_mask(LOG_UNIMP,
+ "host_data_blt: unsupported blit direction %c%c\n",
+ ctx.left_to_right ? '>' : '<',
+ ctx.top_to_bottom ? 'v' : '^');
+ return false;
+ }
+
+ bypp = ctx.bpp / 8;
+
+ if (src_datatype == SRC_COLOR) {
+ pix_count = ATI_HOST_DATA_ACC_BITS / ctx.bpp;
+ memcpy(pix_buf, &s->host_data.acc[0], sizeof(s->host_data.acc));
+ } else {
+ pix_count = ATI_HOST_DATA_ACC_BITS;
+ /* Expand monochrome bits to color pixels */
+ idx = 0;
+ for (int word = 0; word < 4; word++) {
+ for (int byte = 0; byte < 4; byte++) {
+ uint8_t byte_val = s->host_data.acc[word] >> (byte * 8);
+ for (int i = 0; i < 8; i++) {
+ bool is_fg = byte_val & BIT(byte_pix_order ? i : 7 - i);
+ uint32_t color = is_fg ? fg : bg;
+ stn_he_p(&pix_buf[idx], bypp, color);
+ idx += bypp;
+ }
+ }
+ }
+ }
+
+ /* Copy and then modify blit ctx for use in a chunked blit */
+ chunk = ctx;
+ chunk.src_bits = pix_buf;
+ chunk.src.y = 0;
+ chunk.src_stride = ATI_HOST_DATA_ACC_BITS * bypp;
+
+ /* Blit one scanline chunk at a time */
+ row = s->host_data.row;
+ col = s->host_data.col;
+ idx = 0;
+ DPRINTF("blt %dpx @ row: %d, col: %d\n", pix_count, row, col);
+ while (idx < pix_count && row < ctx.dst.height) {
+ unsigned pix_in_scanline = MIN(pix_count - idx,
+ ctx.dst.width - col);
+ chunk.src.x = idx;
+ /* Build a rect for this scanline chunk */
+ chunk.dst.x = ctx.dst.x + col;
+ chunk.dst.y = ctx.dst.y + row;
+ chunk.dst.width = pix_in_scanline;
+ chunk.dst.height = 1;
+ DPRINTF("blt %dpx span @ row: %d, col: %d to dst (%d,%d)\n",
+ pix_in_scanline, row, col, chunk.dst.x, chunk.dst.y);
+ if (ati_2d_do_blt(&chunk, s->use_pixman)) {
+ ati_set_dirty(&s->vga, &chunk);
+ }
+ idx += pix_in_scanline;
+ col += pix_in_scanline;
+ if (col >= ctx.dst.width) {
+ col = 0;
+ row += 1;
+ }
+ }
+
+ /* Track state of the overall blit for use by the next flush */
+ s->host_data.next = 0;
+ s->host_data.row = row;
+ s->host_data.col = col;
+ if (s->host_data.row >= ctx.dst.height) {
+ s->host_data.active = false;
+ }
+
+ return s->host_data.active;
+}
+
+void ati_host_data_finish(ATIVGAState *s)
+{
+ if (ati_host_data_flush(s)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "HOST_DATA blit ended before all data was written\n");
+ }
+ s->host_data.active = false;
+}
diff --git a/hw/display/ati_int.h b/hw/display/ati_int.h
index baa264215c..28f4e9d977 100644
--- a/hw/display/ati_int.h
+++ b/hw/display/ati_int.h
@@ -32,6 +32,7 @@
#define ATI_RAGE128_LINEAR_APER_SIZE (64 * MiB)
#define ATI_R100_LINEAR_APER_SIZE (128 * MiB)
+#define ATI_HOST_DATA_ACC_BITS 128
#define TYPE_ATI_VGA "ati-vga"
OBJECT_DECLARE_SIMPLE_TYPE(ATIVGAState, ATI_VGA)
@@ -126,5 +127,7 @@ struct ATIVGAState {
const char *ati_reg_name(int num);
void ati_2d_blt(ATIVGAState *s);
+bool ati_host_data_flush(ATIVGAState *s);
+void ati_host_data_finish(ATIVGAState *s);
#endif /* ATI_INT_H */
diff --git a/hw/display/ati_regs.h b/hw/display/ati_regs.h
index 48f15e9b1d..b813fa119e 100644
--- a/hw/display/ati_regs.h
+++ b/hw/display/ati_regs.h
@@ -397,7 +397,11 @@
#define DST_32BPP 0x00000006
#define DP_DST_DATATYPE 0x0000000f
#define DP_BRUSH_DATATYPE 0x00000f00
+#define SRC_MONO_FRGD_BKGD 0x00000000
+#define SRC_MONO_FRGD 0x00010000
+#define SRC_COLOR 0x00030000
#define DP_SRC_DATATYPE 0x00030000
+#define DP_BYTE_PIX_ORDER 0x40000000
#define BRUSH_SOLIDCOLOR 0x00000d00
