ati_2d_blt remains the public interface to the blitter but the bulk of
the implementation is moved down into ati_2d_do_blt which is passed an
ATI2DCtx.

ati_2d_do_blt returns a bool that is true when the blit succeeded, which
means that a screen region will need to be set dirty. Otherwise false is
returned.

Signed-off-by: Chad Jablonski <chad@jablonski.xyz>
Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu>
---
 hw/display/ati_2d.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/hw/display/ati_2d.c b/hw/display/ati_2d.c
index f1536e5425..df8975d9d7 100644
--- a/hw/display/ati_2d.c
+++ b/hw/display/ati_2d.c
@@ -123,27 +123,24 @@ static void setup_2d_blt_ctx(const ATIVGAState *s, ATI2DCtx *ctx)
             (ctx->top_to_bottom ? 'v' : '^'));
 }
 
-void ati_2d_blt(ATIVGAState *s)
+static bool ati_2d_do_blt(ATIVGAState *s, ATI2DCtx *ctx)
 {
     bool use_pixman_fill = s->use_pixman & BIT(0);
     bool use_pixman_blt = s->use_pixman & BIT(1);
-    ATI2DCtx ctx_;
-    ATI2DCtx *ctx = &ctx_;
-    setup_2d_blt_ctx(s, ctx);
     if (!ctx->bpp) {
         qemu_log_mask(LOG_GUEST_ERROR, "Invalid bpp\n");
-        return;
+        return false;
     }
     if (!ctx->dst_stride) {
         qemu_log_mask(LOG_GUEST_ERROR, "Zero dest pitch\n");
-        return;
+        return false;
     }
     int dst_stride_words = ctx->dst_stride / sizeof(uint32_t);
     if (ctx->dst.x > 0x3fff || ctx->dst.y > 0x3fff
         || ctx->dst_bits >= ctx->vram_end || ctx->dst_bits + ctx->dst.x
          + (ctx->dst.y + ctx->dst.height) * ctx->dst_stride >= ctx->vram_end) {
         qemu_log_mask(LOG_UNIMP, "blt outside vram not implemented\n");
-        return;
+        return false;
     }
     switch (ctx->rop3) {
     case ROP3_SRCCOPY:
@@ -151,7 +148,7 @@ void ati_2d_blt(ATIVGAState *s)
         bool fallback = false;
         if (!ctx->src_stride) {
             qemu_log_mask(LOG_GUEST_ERROR, "Zero source pitch\n");
-            return;
+            return false;
         }
         int src_stride_words = ctx->src_stride / sizeof(uint32_t);
         if (ctx->src.x > 0x3fff || ctx->src.y > 0x3fff
@@ -159,7 +156,7 @@ void ati_2d_blt(ATIVGAState *s)
             || ctx->src_bits + ctx->src.x + (ctx->src.y + ctx->dst.height)
              * ctx->src_stride >= ctx->vram_end) {
             qemu_log_mask(LOG_UNIMP, "blt outside vram not implemented\n");
-            return;
+            return false;
         }
 
         DPRINTF("pixman_blt(%p, %p, %d, %d, %d, %d, %d, %d, %d, %d, %d, %d)\n",
@@ -262,8 +259,17 @@ void ati_2d_blt(ATIVGAState *s)
     default:
         qemu_log_mask(LOG_UNIMP, "Unimplemented ati_2d blt op %x\n",
                       ctx->rop3 >> 16);
-        return;
+        return false;
     }
 
-    ati_set_dirty(&s->vga, ctx);
+    return true;
+}
+
+void ati_2d_blt(ATIVGAState *s)
+{
+    ATI2DCtx ctx;
+    setup_2d_blt_ctx(s, &ctx);
+    if (ati_2d_do_blt(s, &ctx)) {
+        ati_set_dirty(&s->vga, &ctx);
+    }
 }
-- 
2.52.0