Index: src/mesa/x86/read_rgba_span_x86.S
===================================================================
RCS file: /cvs/mesa/Mesa/src/mesa/x86/read_rgba_span_x86.S,v
retrieving revision 1.4
diff -u -d -r1.4 read_rgba_span_x86.S
--- src/mesa/x86/read_rgba_span_x86.S	4 Jan 2005 14:33:47 -0000	1.4
+++ src/mesa/x86/read_rgba_span_x86.S	5 Mar 2005 00:48:03 -0000
@@ -92,7 +92,7 @@
 	movl	12(%esp), %ecx	/* destination pointer */
 
 	testl	%edx, %edx
-	je	.L20		/* Bail if there's nothing to do. */
+	jle	.L20		/* Bail if there's nothing to do. */
 
 	movl	%ebx, %eax
 
@@ -189,6 +189,9 @@
 	movl	24(%esp), %edx	/* number of pixels to copy */
 	movl	20(%esp), %ecx	/* destination pointer */
 
+	testl	%edx, %edx
+	jle	.L35		/* Bail if there's nothing to do. */
+
 	movl	%esp, %ebp
 	subl	$16, %esp
 	andl	$0xfffffff0, %esp
@@ -348,6 +351,9 @@
 	movl	%ebx, %eax
 	movl	%edx, %esi
 
+	testl	%edx, %edx
+	jle	.L46		/* Bail if there's nothing to do. */
+
 	/* If the source pointer isn't a multiple of 16 we have to process
 	 * a few pixels the "slow" way to get the address aligned for
 	 * the SSE fetch intsructions.
@@ -528,7 +534,8 @@
 	movq	prescale, %mm6
 	movq	scale, %mm7
 
-	shrl	$2, %ecx
+	sarl	$2, %ecx
+	jlt	.L01		/* Bail early if the count is negative. */
 	jmp	.L02
 
 .L03: