Messages in this thread | | | Date | Fri, 08 Nov 2013 11:04:19 -0800 | From | Stephen Boyd <> | Subject | Re: [PATCH] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions |
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On 11/08/13 09:02, Måns Rullgård wrote: > Stephen Boyd <sboyd@codeaurora.org> writes: > >> +int __aeabi_idiv(int numerator, int denominator) >> +{ >> + if (static_key_false(&cpu_has_idiv)) { >> + int ret; >> + >> + asm volatile ( >> + ".arch_extension idiv\n" >> + "sdiv %0, %1, %2" >> + : "=&r" (ret) > There is no need for the & in the output constraint. Dropping it allows > using one of the source registers as destination which may sometimes be > beneficial.
Ok. Thanks. That does seem to improve things.
before:
00000000 <__aeabi_idiv>: 0: e320f000 nop {0} 4: eafffffe b 0 <___aeabi_idiv> 8: e713f110 sdiv r3, r0, r1 c: e1a00003 mov r0, r3 10: e12fff1e bx lr
00000014 <__aeabi_uidiv>: 14: e320f000 nop {0} 18: eafffffe b 0 <___aeabi_uidiv> 1c: e733f110 udiv r3, r0, r1 20: e1a00003 mov r0, r3 24: e12fff1e bx lr
after:
00000000 <__aeabi_idiv>: 0: e320f000 nop {0} 4: eafffffe b 0 <___aeabi_idiv> 8: e710f110 sdiv r0, r0, r1 c: e12fff1e bx lr
00000010 <__aeabi_uidiv>: 10: e320f000 nop {0} 14: eafffffe b 0 <___aeabi_uidiv> 18: e730f110 udiv r0, r0, r1 1c: e12fff1e bx lr
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