[Qemu-devel] [PATCH] Allow microMIPS SWP and SDP to have RD equal to BASE.

[Qemu-devel] [PATCH] Allow microMIPS SWP and SDP to have RD equal to BASE.

[Eric Johnson]

The microMIPS SWP and SDP instructions do not modify GPRs.  So their
behavior is well defined when RD equals BASE.  The MIPS Architecture
Verification Programs (AVPs) check that they work as expected.  This
is required for AVPs to pass.

Signed-off-by: Eric Johnson <ericj@mips.com>
---
 target-mips/translate.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

The patch applies to a8467c7a0e8b024a18608ff7db31ca2f2297e641.

diff --git a/target-mips/translate.c b/target-mips/translate.c
index d5b1c76..82cf75b 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -10034,7 +10034,7 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd,
     const char *opn = "ldst_pair";
     TCGv t0, t1;
 
-    if (ctx->hflags & MIPS_HFLAG_BMASK || rd == 31 || rd == base) {
+    if (ctx->hflags & MIPS_HFLAG_BMASK || rd == 31) {
         generate_exception(ctx, EXCP_RI);
         return;
     }
@@ -10046,6 +10046,10 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd,
 
     switch (opc) {
     case LWP:
+        if (rd == base) {
+            generate_exception(ctx, EXCP_RI);
+            return;
+        }
         save_cpu_state(ctx, 0);
         op_ld_lw(t1, t0, ctx);
         gen_store_gpr(t1, rd);
@@ -10067,6 +10071,10 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd,
         break;
 #ifdef TARGET_MIPS64
     case LDP:
+        if (rd == base) {
+            generate_exception(ctx, EXCP_RI);
+            return;
+        }
         save_cpu_state(ctx, 0);
         op_ld_ld(t1, t0, ctx);
         gen_store_gpr(t1, rd);

Re: [Qemu-devel] [PATCH] Allow microMIPS SWP and SDP to have RD equal to BASE.

[Aurelien Jarno]

On Sat, Sep 17, 2011 at 05:28:16PM -0700, Eric Johnson wrote:
> The microMIPS SWP and SDP instructions do not modify GPRs.  So their
> behavior is well defined when RD equals BASE.  The MIPS Architecture
> Verification Programs (AVPs) check that they work as expected.  This
> is required for AVPs to pass.
> 
> Signed-off-by: Eric Johnson <ericj@mips.com>
> ---
>  target-mips/translate.c |   10 +++++++++-
>  1 files changed, 9 insertions(+), 1 deletions(-)
> 
> The patch applies to a8467c7a0e8b024a18608ff7db31ca2f2297e641.
> 
> diff --git a/target-mips/translate.c b/target-mips/translate.c
> index d5b1c76..82cf75b 100644
> --- a/target-mips/translate.c
> +++ b/target-mips/translate.c
> @@ -10034,7 +10034,7 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd,
>      const char *opn = "ldst_pair";
>      TCGv t0, t1;
>  
> -    if (ctx->hflags & MIPS_HFLAG_BMASK || rd == 31 || rd == base) {
> +    if (ctx->hflags & MIPS_HFLAG_BMASK || rd == 31) {
>          generate_exception(ctx, EXCP_RI);
>          return;
>      }
> @@ -10046,6 +10046,10 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd,
>  
>      switch (opc) {
>      case LWP:
> +        if (rd == base) {
> +            generate_exception(ctx, EXCP_RI);
> +            return;
> +        }
>          save_cpu_state(ctx, 0);
>          op_ld_lw(t1, t0, ctx);
>          gen_store_gpr(t1, rd);
> @@ -10067,6 +10071,10 @@ static void gen_ldst_pair (DisasContext *ctx, uint32_t opc, int rd,
>          break;
>  #ifdef TARGET_MIPS64
>      case LDP:
> +        if (rd == base) {
> +            generate_exception(ctx, EXCP_RI);
> +            return;
> +        }
>          save_cpu_state(ctx, 0);
>          op_ld_ld(t1, t0, ctx);
>          gen_store_gpr(t1, rd);
> 
> 

Thanks, applied.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net