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[PATCH 2/2] tcg/riscv: Use BEXTI for single-bit extractions

Richard Henderson posted 2 patches 3 months ago
[PATCH 2/2] tcg/riscv: Use BEXTI for single-bit extractions
Posted by Richard Henderson 3 months ago 
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/riscv/tcg-target-has.h |  8 +++++++-
 tcg/riscv/tcg-target.c.inc | 13 +++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/tcg/riscv/tcg-target-has.h b/tcg/riscv/tcg-target-has.h
index 10e61edc45..ea38ee5cbb 100644
--- a/tcg/riscv/tcg-target-has.h
+++ b/tcg/riscv/tcg-target-has.h
@@ -64,7 +64,13 @@ tcg_target_extract_valid(TCGType type, unsigned ofs, unsigned len)
         /* ofs > 0 uses SRLIW; ofs == 0 uses add.uw. */
         return ofs || (cpuinfo & CPUINFO_ZBA);
     }
-    return (cpuinfo & CPUINFO_ZBB) && ofs == 0 && len == 16;
+    switch (len) {
+    case 1:
+        return (cpuinfo & CPUINFO_ZBS) && ofs != 0;
+    case 16:
+        return (cpuinfo & CPUINFO_ZBB) && ofs == 0;
+    }
+    return false;
 }
 #define TCG_TARGET_extract_valid  tcg_target_extract_valid
 
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 12c3cffcc0..83ec7cd980 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -162,6 +162,7 @@ typedef enum {
     OPC_ANDI = 0x7013,
     OPC_AUIPC = 0x17,
     OPC_BEQ = 0x63,
+    OPC_BEXTI = 0x48005013,
     OPC_BGE = 0x5063,
     OPC_BGEU = 0x7063,
     OPC_BLT = 0x4063,
@@ -2307,9 +2308,17 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, TCGType type,
             } else {
                 tcg_out_opc_imm(s, OPC_SRLIW, a0, a1, a2);
             }
-        } else if (a2 == 0 && args[3] == 16) {
+            break;
+        }
+        switch (args[3]) {
+        case 1:
+            tcg_out_opc_imm(s, OPC_BEXTI, a0, a1, a2);
+            break;
+        case 16:
+            tcg_debug_assert(a2 == 0);
             tcg_out_ext16u(s, a0, a1);
-        } else {
+            break;
+        default:
             g_assert_not_reached();
         }
         break;
-- 
2.43.0
Re: [PATCH 2/2] tcg/riscv: Use BEXTI for single-bit extractions
Posted by Philippe Mathieu-Daudé 2 months, 4 weeks ago 
Hi Richard,

On 2/1/25 19:16, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   tcg/riscv/tcg-target-has.h |  8 +++++++-
>   tcg/riscv/tcg-target.c.inc | 13 +++++++++++--
>   2 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/tcg/riscv/tcg-target-has.h b/tcg/riscv/tcg-target-has.h
> index 10e61edc45..ea38ee5cbb 100644
> --- a/tcg/riscv/tcg-target-has.h
> +++ b/tcg/riscv/tcg-target-has.h
> @@ -64,7 +64,13 @@ tcg_target_extract_valid(TCGType type, unsigned ofs, unsigned len)
>           /* ofs > 0 uses SRLIW; ofs == 0 uses add.uw. */
>           return ofs || (cpuinfo & CPUINFO_ZBA);
>       }
> -    return (cpuinfo & CPUINFO_ZBB) && ofs == 0 && len == 16;
> +    switch (len) {
> +    case 1:
> +        return (cpuinfo & CPUINFO_ZBS) && ofs != 0;

Why can't we have ofs=0?

> +    case 16:
> +        return (cpuinfo & CPUINFO_ZBB) && ofs == 0;
> +    }
> +    return false;
>   }
>   #define TCG_TARGET_extract_valid  tcg_target_extract_valid
>   
> diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
> index 12c3cffcc0..83ec7cd980 100644
> --- a/tcg/riscv/tcg-target.c.inc
> +++ b/tcg/riscv/tcg-target.c.inc
> @@ -162,6 +162,7 @@ typedef enum {
>       OPC_ANDI = 0x7013,
>       OPC_AUIPC = 0x17,
>       OPC_BEQ = 0x63,
> +    OPC_BEXTI = 0x48005013,
>       OPC_BGE = 0x5063,
>       OPC_BGEU = 0x7063,
>       OPC_BLT = 0x4063,
> @@ -2307,9 +2308,17 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, TCGType type,
>               } else {
>                   tcg_out_opc_imm(s, OPC_SRLIW, a0, a1, a2);
>               }
> -        } else if (a2 == 0 && args[3] == 16) {
> +            break;
> +        }
> +        switch (args[3]) {
> +        case 1:
> +            tcg_out_opc_imm(s, OPC_BEXTI, a0, a1, a2);
> +            break;
> +        case 16:
> +            tcg_debug_assert(a2 == 0);
>               tcg_out_ext16u(s, a0, a1);
> -        } else {
> +            break;
> +        default:
>               g_assert_not_reached();
>           }
>           break;
Re: [PATCH 2/2] tcg/riscv: Use BEXTI for single-bit extractions
Posted by Richard Henderson 2 months, 4 weeks ago 
On 1/7/25 02:29, Philippe Mathieu-Daudé wrote:
> Hi Richard,
> 
> On 2/1/25 19:16, Richard Henderson wrote:
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   tcg/riscv/tcg-target-has.h |  8 +++++++-
>>   tcg/riscv/tcg-target.c.inc | 13 +++++++++++--
>>   2 files changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/tcg/riscv/tcg-target-has.h b/tcg/riscv/tcg-target-has.h
>> index 10e61edc45..ea38ee5cbb 100644
>> --- a/tcg/riscv/tcg-target-has.h
>> +++ b/tcg/riscv/tcg-target-has.h
>> @@ -64,7 +64,13 @@ tcg_target_extract_valid(TCGType type, unsigned ofs, unsigned len)
>>           /* ofs > 0 uses SRLIW; ofs == 0 uses add.uw. */
>>           return ofs || (cpuinfo & CPUINFO_ZBA);
>>       }
>> -    return (cpuinfo & CPUINFO_ZBB) && ofs == 0 && len == 16;
>> +    switch (len) {
>> +    case 1:
>> +        return (cpuinfo & CPUINFO_ZBS) && ofs != 0;
> 
> Why can't we have ofs=0?

To prefer ANDI.


r~
Re: [PATCH 2/2] tcg/riscv: Use BEXTI for single-bit extractions
Posted by Alistair Francis 3 months ago 
On Fri, Jan 3, 2025 at 4:21 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Acked-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  tcg/riscv/tcg-target-has.h |  8 +++++++-
>  tcg/riscv/tcg-target.c.inc | 13 +++++++++++--
>  2 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/tcg/riscv/tcg-target-has.h b/tcg/riscv/tcg-target-has.h
> index 10e61edc45..ea38ee5cbb 100644
> --- a/tcg/riscv/tcg-target-has.h
> +++ b/tcg/riscv/tcg-target-has.h
> @@ -64,7 +64,13 @@ tcg_target_extract_valid(TCGType type, unsigned ofs, unsigned len)
>          /* ofs > 0 uses SRLIW; ofs == 0 uses add.uw. */
>          return ofs || (cpuinfo & CPUINFO_ZBA);
>      }
> -    return (cpuinfo & CPUINFO_ZBB) && ofs == 0 && len == 16;
> +    switch (len) {
> +    case 1:
> +        return (cpuinfo & CPUINFO_ZBS) && ofs != 0;
> +    case 16:
> +        return (cpuinfo & CPUINFO_ZBB) && ofs == 0;
> +    }
> +    return false;
>  }
>  #define TCG_TARGET_extract_valid  tcg_target_extract_valid
>
> diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
> index 12c3cffcc0..83ec7cd980 100644
> --- a/tcg/riscv/tcg-target.c.inc
> +++ b/tcg/riscv/tcg-target.c.inc
> @@ -162,6 +162,7 @@ typedef enum {
>      OPC_ANDI = 0x7013,
>      OPC_AUIPC = 0x17,
>      OPC_BEQ = 0x63,
> +    OPC_BEXTI = 0x48005013,
>      OPC_BGE = 0x5063,
>      OPC_BGEU = 0x7063,
>      OPC_BLT = 0x4063,
> @@ -2307,9 +2308,17 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, TCGType type,
>              } else {
>                  tcg_out_opc_imm(s, OPC_SRLIW, a0, a1, a2);
>              }
> -        } else if (a2 == 0 && args[3] == 16) {
> +            break;
> +        }
> +        switch (args[3]) {
> +        case 1:
> +            tcg_out_opc_imm(s, OPC_BEXTI, a0, a1, a2);
> +            break;
> +        case 16:
> +            tcg_debug_assert(a2 == 0);
>              tcg_out_ext16u(s, a0, a1);
> -        } else {
> +            break;
> +        default:
>              g_assert_not_reached();
>          }
>          break;
> --
> 2.43.0
>
>

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