[PATCH] Sparc longlong.h enhancements.

[Eric Botcazou]

> Eric, while looking at soft-fp code generated in glibc I noticed that
> for v9 on 32-bit we end up doing software multiplies and divides :-/
>
> I also noticed that the two-limb addition and subtraction could be
> done using a branchless sequence on 64-bit.
>
> Any objections?

None on principle, but...

>  #if ((defined (__sparc__) && defined (__arch64__)) || defined (__sparcv9))
> \ && W_TYPE_SIZE == 64
>  #define add_ssaaaa(sh, sl, ah, al, bh, bl)				\
> -  __asm__ ("addcc %r4,%5,%1\n\t"					\
> -   	   "add %r2,%3,%0\n\t"						\
> -   	   "bcs,a,pn %%xcc, 1f\n\t"					\
> -   	   "add %0, 1, %0\n"						\
> -	   "1:"								\
> +  do {									\
> +    UDItype __carry = 0;						\
> +    __asm__ ("addcc\t%r5,%6,%1\n\t"					\
> +	     "add\t%r3,%4,%0\n\t"					\
> +	     "movcs\t%%xcc, 1, %2\n\t"					\
> +             "add\t%0, %2, %0"						\
>
>  	   : "=r" ((UDItype)(sh)),				      	\
>
> -	     "=&r" ((UDItype)(sl))				      	\
> +	     "=&r" ((UDItype)(sl)),				      	\
> +	     "=&r" (__carry)				      		\
>
>  	   : "%rJ" ((UDItype)(ah)),				     	\
>
>  	     "rI" ((UDItype)(bh)),				      	\
>  	     "%rJ" ((UDItype)(al)),				     	\
> -	     "rI" ((UDItype)(bl))				       	\
> -	   __CLOBBER_CC)
> +	     "rI" ((UDItype)(bl)),				       	\
> +	     "2" (__carry)				       		\
> +	   __CLOBBER_CC);						\
> +  } while (0)

If __carry is used as both source and destination for %2, why not use a single 
operand with the + modifier?

> -#define sub_ddmmss(sh, sl, ah, al, bh, bl) 				\
> -  __asm__ ("subcc %r4,%5,%1\n\t"					\
> -   	   "sub %r2,%3,%0\n\t"						\
> -   	   "bcs,a,pn %%xcc, 1f\n\t"					\
> -   	   "sub %0, 1, %0\n\t"						\
> -	   "1:"								\
> +#define sub_ddmmss(sh, sl, ah, al, bh, bl)				\
> +  do {									\
> +    UDItype __carry = 0;						\
> +    __asm__ ("subcc\t%r5,%6,%1\n\t"					\
> +	     "sub\t%r3,%4,%0\n\t"					\
> +	     "movcs\t%%xcc, 1, %2\n\t"					\
> +             "add\t%0, %2, %0"						\
>
>  	   : "=r" ((UDItype)(sh)),				      	\
>
> -	     "=&r" ((UDItype)(sl))				      	\
> -	   : "rJ" ((UDItype)(ah)),				     	\
> +	     "=&r" ((UDItype)(sl)),				      	\
> +	     "=&r" (__carry)				      		\
> +	   : "%rJ" ((UDItype)(ah)),				     	\
>  	     "rI" ((UDItype)(bh)),				      	\
> -	     "rJ" ((UDItype)(al)),				     	\
> -	     "rI" ((UDItype)(bl))				       	\
> -	   __CLOBBER_CC)
> +	     "%rJ" ((UDItype)(al)),				     	\
> +	     "rI" ((UDItype)(bl)),				       	\
> +	     "2" (__carry)				       		\
> +	   __CLOBBER_CC);						\
> +  } while (0)

Likewise.

-- 
Eric Botcazou