radeon_accel: Avoid unaligned access in RADEONCopySwap

from NetBSD (via Martin Husemann), this helps the radeon driver
work on sparc64 hardware.

Signed-off-by: Nia Alarie <nia@NetBSD.org>
Part-of: <https://gitlab.freedesktop.org/xorg/driver/xf86-video-ati/-/merge_requests/22>

1 files changed, 24 insertions, 1 deletions

diff --git a/src/radeon_accel.c b/src/radeon_accel.c
index 8d4e76a5..a0dca68c 100644
--- a/src/radeon_accel.c
+++ b/src/radeon_accel.c
@@ -142,7 +142,30 @@ void RADEONCopySwap(uint8_t *dst, uint8_t *src, unsigned int size, int swap)
 	    return;
         }
     case RADEON_HOST_DATA_SWAP_32BIT:
-        {
+	if (((uintptr_t)dst & 1) || ((uintptr_t)src & 1)) {
+	    uint8_t *d = (uint8_t *)dst;
+	    uint8_t *s = (uint8_t *)src;
+	    unsigned int nwords = size >> 2;
+
+	    for (; nwords > 0; --nwords, d+=4, s+=4) {
+	        d[0] = s[3];
+		d[1] = s[2];
+		d[2] = s[1];
+		d[3] = s[0];
+	    }
+	    return;
+        } else if (((uintptr_t)dst & 3) || ((uintptr_t)src & 3)) {
+	    /* copy 16bit wise */
+	    uint16_t *d = (uint16_t *)dst;
+	    uint16_t *s = (uint16_t *)src;
+	    unsigned int nwords = size >> 2;
+
+	    for (; nwords > 0; --nwords, d+=2, s+=2) {
+	        d[0] = ((s[1] >> 8) & 0xff) | ((s[1] & 0xff) << 8);
+	        d[1] = ((s[0] >> 8) & 0xff) | ((s[0] & 0xff) << 8);
+	    }
+	    return;
+	} else {
 	    unsigned int *d = (unsigned int *)dst;
 	    unsigned int *s = (unsigned int *)src;
 	    unsigned int nwords = size >> 2;