Re: [Qemu-devel] [PATCH v2 00/13] tcg/sparc v8plus code generation

[Richard Henderson]

On 07/15/2015 09:54 PM, Aurelien Jarno wrote:
> While I understand why we need the new trunc_shr_i32 opcode for MIPS64
> (the 32-bit values must be kept sign-extended), I currently fail to
> see why it is needed for SPARC.

As far as I recall, it improves code for extracting high parts of 64-bit 
quantities.  Without this, we wind up with a 64-bit shift, requiring a 64-bit 
temp register, followed by the "real" truncate which can copy the data to a 
32-bit destination register.


r~