On 18/12/2018 09:49, Mark Cave-Ayland wrote:
> A quick bisection suggests that there could be 2 separate issues related to
> the
> implementation of splat:
>
> Patch "target/ppc: convert vspltis[bhw] to use vector operations" causes a
> black
> border to appear around the OS X splash screen
> (https://www.ilande.co.uk/tmp/qemu/badapple1.png) which may suggest an
> overflow/alignment issue.
This one appears to be a sign extension issue - if I make use of the same
technique
used by the previous helper then this problem goes away. Below is my
experimental
diff to be squashed into "target/ppc: convert vspltis[bhw] to use vector
operations":
diff --git a/target/ppc/translate/vmx-impl.inc.c
b/target/ppc/translate/vmx-impl.inc.c
index be638cdb1a..6cd25c8dc6 100644
--- a/target/ppc/translate/vmx-impl.inc.c
+++ b/target/ppc/translate/vmx-impl.inc.c
@@ -723,12 +723,12 @@ GEN_VXRFORM_DUAL(vcmpgtfp, PPC_ALTIVEC, PPC_NONE, \
#define GEN_VXFORM_DUPI(name, tcg_op, opc2, opc3) \
static void glue(gen_, name)(DisasContext *ctx) \
{ \
- int simm; \
+ int8_t simm; \
if (unlikely(!ctx->altivec_enabled)) { \
gen_exception(ctx, POWERPC_EXCP_VPU); \
return; \
} \
- simm = SIMM5(ctx->opcode); \
+ simm = (int8_t)(SIMM5(ctx->opcode) << 3) >> 3; \
tcg_op(avr64_offset(rD(ctx->opcode), true), 16, 16, simm); \
}
ATB,
Mark.
