Prefer CPS over MSR for PSR manipulation. Use UDIV/SDIV for general-purpose...
Prefer CPS over MSR for PSR manipulation. Use UDIV/SDIV for general-purpose division, and UMULL for /10. Detail: s/k_body: - _kernel_irqs_off and _kernel_irqs_on now use CPS for disabling/enabling IRQs as opposed to MSR. Apart from being shorter code sequences, it's generally a faster instruction. - __rt_udiv and __rt_sdiv (and aliases) now use the UDIV and SDIV instructions if building for ARMv7VE - __rt_udiv10 and __rt_sdiv10 (and aliases) now use UMULL to multiply by 1/10 when building for targets with long multiply support, as this is faster than the old method. UDIV/SDIV can be fast too, but only for small numbers, making UMULL the best for the general case. Admin: Tested on Cortex-A15 Prototyping of division routines on assorted CPUs shows that UDIV/SDIV is generally between 20% and 400% faster than the old routine (Cortex-A7, Cortex-A53), or up to 1300% faster on Cortex-A15 (the CPU does not like the old routine!) Division by 10 is now about 20% faster across all appropriate CPUs Version 5.89. Tagged as 'RISC_OSLib-5_89'
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