Allow microMIPS SWP and SDP to have RD equal to BASE.

Submitted by Eric Johnson on Sept. 18, 2011, 12:28 a.m.

Details

Message ID 20110918002816.GA10076@linux-ericj.mips.com
State New
Headers show

Commit Message

Eric Johnson Sept. 18, 2011, 12:28 a.m.
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.

Comments

Aurelien Jarno Aug. 27, 2012, 11:45 a.m.
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.

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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);