morello atomic: Trim gcvalue from the spin loop of arithmetic atomics #2249
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Use a ptraddr_t as the input that can be assigned to the register constraint as is done for RISC-V. This allows the compiler to either hoist the gcvalue out of the loop, or to just use the x portion of the relevant register.
bsdjhb
commented
Nov 16, 2024
| @@ -667,21 +667,19 @@ static __inline void \ | |||
| atomic_##op##_##bar##ptr(volatile uintptr_t *p, uintptr_t val) \ | |||
| { \ | |||
| uintptr_t previous; \ | |||
| ptraddr_t tmp1, tmp2; \ | |||
| ptraddr_t tmp; \ | |||
| int res; \ | |||
| \ | |||
| __asm __volatile( \ | |||
| "1:" \ | |||
| "ld" #a "xr %0, [%4]\n" \ | |||
| "gcvalue %2, %0\n" \ | |||
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This could be eliminated if there was an equivalent to %wN to denote the X version of the C register as then we could use that as the second operand in the scvalue instruction below.
jrtc27
approved these changes
Nov 20, 2024
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Use a ptraddr_t as the input that can be assigned to the register
constraint as is done for RISC-V. This allows the compiler to either
hoist the gcvalue out of the loop, or to just use the x portion of the
relevant register.