Hi Paolo,
On 5/12/21 2:51 PM, Paolo Bonzini wrote:
> On 12/05/21 15:44, Alexandru Elisei wrote:
>>> + bl __udivmoddi4
>>> + ldr r2, [sp, #8] // remainder returned in r2-r3
>>> + ldr r3, [sp, #12]
>>> + add sp, sp, #16
>>> + pop {r11, pc}
>>
>> I'm not sure what is going on here. Is the function returning 2 64bit arguments as
>> an 128bit vector? Or is the function being called from assembly and this is a
>> convention between it and the caller?
>
> It's an eABI convention that spans the runtime and the compiler.
>
> https://developer.arm.com/documentation/ihi0043/e/?lang=en#standardized-compiler-helper-functions
> says it returns a "pair of (unsigned) long longs is returned in {{r0, r1}, {r2,
> r3}}, the quotient in {r0, r1}, and the remainder in {r2, r3}."
Thanks for the link, the functions are indeed returning the quotient in {r0, r1}
and remainder in {r2, r3} according to the convention:
Reviewed-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Thanks,
Alex
