Re: [Qemu-devel] [PATCH] tcg: add div/rem 32-bit helpers

[malc]

On Sat, 6 Mar 2010, Aurelien Jarno wrote:

> On Sat, Mar 06, 2010 at 09:15:38AM +0200, Blue Swirl wrote:
> > On 3/4/10, Aurelien Jarno <address@hidden> wrote:
> > > Some targets like ARM would benefit to use 32-bit helpers for
> > >  div/rem/divu/remu.
> > >
> > >  Create a #define for div2 so that targets can select between
> > >  div, div2 and helper implementation. Use the helper version if none
> > >  of the #define are present.
> > >
> > >  Signed-off-by: Aurelien Jarno <address@hidden>
> > >  ---
> > >   tcg-runtime.c           |   24 +++++++++++++++++++
> > >   tcg/arm/tcg-target.h    |    1 +
> > >   tcg/hppa/tcg-target.h   |    1 +
> > >   tcg/i386/tcg-target.h   |    1 +
> > >   tcg/tcg-op.h            |   57 
> > > +++++++++++++++++++++++++++++++++++++++++++++-
> > >   tcg/tcg-runtime.h       |    5 ++++
> > >   tcg/x86_64/tcg-target.h |    2 +
> > >   7 files changed, 89 insertions(+), 2 deletions(-)
> > >
> > >  diff --git a/tcg-runtime.c b/tcg-runtime.c
> > >  index 219cade..abfc364 100644
> > >  --- a/tcg-runtime.c
> > >  +++ b/tcg-runtime.c
> > >  @@ -25,6 +25,30 @@
> > >
> > >   #include "tcg/tcg-runtime.h"
> > >
> > >  +/* 32-bit helpers */
> > >  +
> > >  +int32_t tcg_helper_div_i32(int32_t arg1, int32_t arg2)
> > >  +{
> > >  +    return arg1 / arg2;
> > >  +}
> > >  +
> > >  +int32_t tcg_helper_rem_i32(int32_t arg1, int32_t arg2)
> > >  +{
> > >  +    return arg1 % arg2;
> > >  +}
> > >  +
> > >  +uint32_t tcg_helper_divu_i32(uint32_t arg1, uint32_t arg2)
> > >  +{
> > >  +    return arg1 / arg2;
> > >  +}
> > >  +
> > >  +uint32_t tcg_helper_remu_i32(uint32_t arg1, uint32_t arg2)
> > >  +{
> > >  +    return arg1 % arg2;
> > >  +}
> > >  +
> > >  +/* 64-bit helpers */
> > >  +
> > >   int64_t tcg_helper_shl_i64(int64_t arg1, int64_t arg2)
> > >   {
> > >      return arg1 << arg2;
> > >  diff --git a/tcg/arm/tcg-target.h b/tcg/arm/tcg-target.h
> > >  index 4cad967..4b2b0be 100644
> > >  --- a/tcg/arm/tcg-target.h
> > >  +++ b/tcg/arm/tcg-target.h
> > >  @@ -56,6 +56,7 @@ enum {
> > >   #define TCG_TARGET_CALL_STACK_OFFSET   0
> > >
> > >   /* optional instructions */
> > >  +#define TCG_TARGET_HAS_div2_i32
> > 
> > Please also add commented out #defines for targets that do not
> > implement div2 yet.
> 
> I don't really see the point. The targets should implement either
> div/rem or div2, depending on their instruction set. Implementing div2
> on a targets which have separate instructions to compute div and rem 
> will impact the performances negatively.

Seconded.

> 
> > >   #define TCG_TARGET_HAS_ext8s_i32
> > >   #define TCG_TARGET_HAS_ext16s_i32
> > >   // #define TCG_TARGET_HAS_ext8u_i32
> > >  diff --git a/tcg/hppa/tcg-target.h b/tcg/hppa/tcg-target.h
> > >  index 7ab6f0c..fa39bfc 100644
> > >  --- a/tcg/hppa/tcg-target.h
> > >  +++ b/tcg/hppa/tcg-target.h
> > >  @@ -75,6 +75,7 @@ enum {
> > >   #define TCG_TARGET_STACK_GROWSUP
> > >
> > >   /* optional instructions */
> > >  +#define TCG_TARGET_HAS_div2_i32
> > >   //#define TCG_TARGET_HAS_ext8s_i32
> > >   //#define TCG_TARGET_HAS_ext16s_i32
> > >   //#define TCG_TARGET_HAS_bswap16_i32
> > >  diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h
> > >  index f97034c..e994fd5 100644
> > >  --- a/tcg/i386/tcg-target.h
> > >  +++ b/tcg/i386/tcg-target.h
> > >  @@ -45,6 +45,7 @@ enum {
> > >   #define TCG_TARGET_CALL_STACK_OFFSET 0
> > >
> > >   /* optional instructions */
> > >  +#define TCG_TARGET_HAS_div2_i32
> > >   #define TCG_TARGET_HAS_rot_i32
> > >   #define TCG_TARGET_HAS_ext8s_i32
> > >   #define TCG_TARGET_HAS_ext16s_i32
> > >  diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
> > >  index 6ae1760..c71e1a8 100644
> > >  --- a/tcg/tcg-op.h
> > >  +++ b/tcg/tcg-op.h
> > >  @@ -365,6 +365,19 @@ static inline void tcg_gen_helperN(void *func, int 
> > > flags, int sizemask,
> > >   }
> > >
> > >   /* FIXME: Should this be pure?  */
> > >  +static inline void tcg_gen_helper32(void *func, TCGv_i32 ret,
> > >  +                                    TCGv_i32 a, TCGv_i32 b)
> > >  +{
> > >  +    TCGv_ptr fn;
> > >  +    TCGArg args[2];
> > >  +    fn = tcg_const_ptr((tcg_target_long)func);
> > >  +    args[0] = GET_TCGV_I32(a);
> > >  +    args[1] = GET_TCGV_I32(b);
> > >  +    tcg_gen_callN(&tcg_ctx, fn, 0, 0, GET_TCGV_I32(ret), 2, args);
> > >  +    tcg_temp_free_ptr(fn);
> > >  +}
> > >  +
> > >  +/* FIXME: Should this be pure?  */
> > >   static inline void tcg_gen_helper64(void *func, TCGv_i64 ret,
> > >                                      TCGv_i64 a, TCGv_i64 b)
> > >   {
> > >  @@ -635,7 +648,7 @@ static inline void tcg_gen_remu_i32(TCGv_i32 ret, 
> > > TCGv_i32 arg1, TCGv_i32 arg2)
> > >   {
> > >      tcg_gen_op3_i32(INDEX_op_remu_i32, ret, arg1, arg2);
> > >   }
> > >  -#else
> > >  +#elif defined(TCG_TARGET_HAS_div2_i32)
> > >   static inline void tcg_gen_div_i32(TCGv_i32 ret, TCGv_i32 arg1, 
> > > TCGv_i32 arg2)
> > >   {
> > >      TCGv_i32 t0;
> > >  @@ -671,6 +684,26 @@ static inline void tcg_gen_remu_i32(TCGv_i32 ret, 
> > > TCGv_i32 arg1, TCGv_i32 arg2)
> > >      tcg_gen_op5_i32(INDEX_op_divu2_i32, t0, ret, arg1, t0, arg2);
> > >      tcg_temp_free_i32(t0);
> > >   }
> > >  +#else
> > >  +static inline void tcg_gen_div_i32(TCGv_i32 ret, TCGv_i32 arg1, 
> > > TCGv_i32 arg2)
> > >  +{
> > >  +    tcg_gen_helper32(tcg_helper_div_i32, ret, arg1, arg2);
> > >  +}
> > >  +
> > >  +static inline void tcg_gen_rem_i32(TCGv_i32 ret, TCGv_i32 arg1, 
> > > TCGv_i32 arg2)
> > >  +{
> > >  +    tcg_gen_helper32(tcg_helper_rem_i32, ret, arg1, arg2);
> > >  +}
> > >  +
> > >  +static inline void tcg_gen_divu_i32(TCGv_i32 ret, TCGv_i32 arg1, 
> > > TCGv_i32 arg2)
> > >  +{
> > >  +    tcg_gen_helper32(tcg_helper_divu_i32, ret, arg1, arg2);
> > >  +}
> > >  +
> > >  +static inline void tcg_gen_remu_i32(TCGv_i32 ret, TCGv_i32 arg1, 
> > > TCGv_i32 arg2)
> > >  +{
> > >  +    tcg_gen_helper32(tcg_helper_remu_i32, ret, arg1, arg2);
> > >  +}
> > >   #endif
> > >
> > >   #if TCG_TARGET_REG_BITS == 32
> > >  @@ -1135,7 +1168,7 @@ static inline void tcg_gen_remu_i64(TCGv_i64 ret, 
> > > TCGv_i64 arg1, TCGv_i64 arg2)
> > >   {
> > >      tcg_gen_op3_i64(INDEX_op_remu_i64, ret, arg1, arg2);
> > >   }
> > >  -#else
> > >  +#elif defined(TCG_TARGET_HAS_div2_i64)
> > >   static inline void tcg_gen_div_i64(TCGv_i64 ret, TCGv_i64 arg1, 
> > > TCGv_i64 arg2)
> > >   {
> > >      TCGv_i64 t0;
> > >  @@ -1171,6 +1204,26 @@ static inline void tcg_gen_remu_i64(TCGv_i64 ret, 
> > > TCGv_i64 arg1, TCGv_i64 arg2)
> > >      tcg_gen_op5_i64(INDEX_op_divu2_i64, t0, ret, arg1, t0, arg2);
> > >      tcg_temp_free_i64(t0);
> > >   }
> > >  +#else
> > >  +static inline void tcg_gen_div_i64(TCGv_i64 ret, TCGv_i64 arg1, 
> > > TCGv_i64 arg2)
> > >  +{
> > >  +    tcg_gen_helper64(tcg_helper_div_i64, ret, arg1, arg2);
> > >  +}
> > >  +
> > >  +static inline void tcg_gen_rem_i64(TCGv_i64 ret, TCGv_i64 arg1, 
> > > TCGv_i64 arg2)
> > >  +{
> > >  +    tcg_gen_helper64(tcg_helper_rem_i64, ret, arg1, arg2);
> > >  +}
> > >  +
> > >  +static inline void tcg_gen_divu_i64(TCGv_i64 ret, TCGv_i64 arg1, 
> > > TCGv_i64 arg2)
> > >  +{
> > >  +    tcg_gen_helper64(tcg_helper_divu_i64, ret, arg1, arg2);
> > >  +}
> > >  +
> > >  +static inline void tcg_gen_remu_i64(TCGv_i64 ret, TCGv_i64 arg1, 
> > > TCGv_i64 arg2)
> > >  +{
> > >  +    tcg_gen_helper64(tcg_helper_remu_i64, ret, arg1, arg2);
> > >  +}
> > >   #endif
> > >
> > >   #endif
> > >  diff --git a/tcg/tcg-runtime.h b/tcg/tcg-runtime.h
> > >  index e750cc1..5615b13 100644
> > >  --- a/tcg/tcg-runtime.h
> > >  +++ b/tcg/tcg-runtime.h
> > >  @@ -2,6 +2,11 @@
> > >   #define TCG_RUNTIME_H
> > >
> > >   /* tcg-runtime.c */
> > >  +int32_t tcg_helper_div_i32(int32_t arg1, int32_t arg2);
> > >  +int32_t tcg_helper_rem_i32(int32_t arg1, int32_t arg2);
> > >  +uint32_t tcg_helper_divu_i32(uint32_t arg1, uint32_t arg2);
> > >  +uint32_t tcg_helper_remu_i32(uint32_t arg1, uint32_t arg2);
> > >  +
> > >   int64_t tcg_helper_shl_i64(int64_t arg1, int64_t arg2);
> > >   int64_t tcg_helper_shr_i64(int64_t arg1, int64_t arg2);
> > >   int64_t tcg_helper_sar_i64(int64_t arg1, int64_t arg2);
> > >  diff --git a/tcg/x86_64/tcg-target.h b/tcg/x86_64/tcg-target.h
> > >  index 765f0b4..d1e8b9e 100644
> > >  --- a/tcg/x86_64/tcg-target.h
> > >  +++ b/tcg/x86_64/tcg-target.h
> > >  @@ -56,6 +56,8 @@ enum {
> > >   #define TCG_TARGET_CALL_STACK_OFFSET 0
> > >
> > >   /* optional instructions */
> > >  +#define TCG_TARGET_HAS_div2_i32
> > >  +#define TCG_TARGET_HAS_div2_i64
> > >   #define TCG_TARGET_HAS_bswap16_i32
> > >   #define TCG_TARGET_HAS_bswap16_i64
> > >   #define TCG_TARGET_HAS_bswap32_i32
> > >
> > > --
> > >  1.7.0
> > >
> > >
> > >
> > >
> > 
> > 
> > 
> 
> 

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