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 <chad@jablonski.xyz>
---
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
--
2.52.0On 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 <chad@jablonski.xyz>
Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu>
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
>
>
> > Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu> > > 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, This is great! Thank you Zoltan for all of your time and patience reviewing.
On Tue, 3 Mar 2026, Chad Jablonski wrote: >> Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu> >> >> 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, > > This is great! Thank you Zoltan for all of your time and patience > reviewing. Thank you for taking up this work and not giving up and doing an excellent work testing real cards and modelling it. Now we just need somebody to pick up the patches so it can be merged. Hopefully somebody is still reading this thread. Regards, BALATON Zoltan
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