File 0197-sm501-Implement-negated-destination.patch of Package qemu.20395

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File 0197-sm501-Implement-negated-destination.patch of Package qemu.20395

From: Sebastian Bauer <mail@sebastianbauer.info>
Date: Wed, 4 Jul 2018 11:40:58 +0200
Subject: sm501: Implement negated destination raster operation mode

Git-commit: debc7e7dad1e70c03d585d96625da0038eba375c
References: bsc#1172385, CVE-2020-12829

Add support for the negated destination operation mode. This is used e.g.
by AmigaOS for the INVERSEVID drawing mode. With this change, the cursor
in the shell and non-immediate window adjustment are working now.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/display/sm501.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/hw/display/sm501.c b/hw/display/sm501.c
index 58986355b2457952eb3d1821a50e..48b5b1afd94283471ce74333e9c0 100644
--- a/hw/display/sm501.c
+++ b/hw/display/sm501.c
@@ -687,6 +687,8 @@ static void sm501_2d_operation(SM501State *s)
     uint32_t color = s->twoD_foreground;
     int format_flags = (s->twoD_stretch >> 20) & 0x3;
     int addressing = (s->twoD_stretch >> 16) & 0xF;
+    int rop_mode = (s->twoD_control >> 15) & 0x1; /* 1 for rop2, else rop3 */
+    int rop = s->twoD_control & 0xFF;
 
     /* get frame buffer info */
     uint8_t *src = s->local_mem + (s->twoD_source_base & 0x03FFFFFF);
@@ -711,6 +713,8 @@ static void sm501_2d_operation(SM501State *s)
         int y, x, index_d, index_s;                                           \
         for (y = 0; y < operation_height; y++) {                              \
             for (x = 0; x < operation_width; x++) {                           \
+                _pixel_type val;                                              \
+                                                                              \
                 if (rtl) {                                                    \
                     index_s = ((src_y - y) * src_width + src_x - x) * _bpp;   \
                     index_d = ((dst_y - y) * dst_width + dst_x - x) * _bpp;   \
@@ -718,7 +722,13 @@ static void sm501_2d_operation(SM501State *s)
                     index_s = ((src_y + y) * src_width + src_x + x) * _bpp;   \
                     index_d = ((dst_y + y) * dst_width + dst_x + x) * _bpp;   \
                 }                                                             \
-                *(_pixel_type *)&dst[index_d] = *(_pixel_type *)&src[index_s];\
+                if (rop_mode == 1 && rop == 5) {                              \
+                    /* Invert dest */                                         \
+                    val = ~*(_pixel_type *)&dst[index_d];                     \
+                } else {                                                      \
+                    val = *(_pixel_type *)&src[index_s];                      \
+                }                                                             \
+                *(_pixel_type *)&dst[index_d] = val;                          \
             }                                                                 \
         }                                                                     \
     }

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File 0197-sm501-Implement-negated-destination.patch of Package qemu.20395

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