Re: [Qemu-devel] Question about comment on MIPS POOL32AXF encoding

[Johnson, Eric]

> -----Original Message-----
> From: address@hidden [mailto:qemu-devel-
> address@hidden On Behalf Of ??? (Wei-Ren Chen)
> Sent: Thursday, November 15, 2012 1:03 AM
> To: address@hidden
> Cc: Jia Liu
> Subject: [Qemu-devel] Question about comment on MIPS POOL32AXF encoding
> 
> Hi all,
> 
>   I am reading POOL32AXF encoding in target-mips/translate.c,
> and can't understand what the comment says. For example,
> 
>     /* bits 13..12 for 0x01 */
>     MFHI_ACC = 0x0,
>     MFLO_ACC = 0x1,
>     MTHI_ACC = 0x2,
>     MTLO_ACC = 0x3,
> 
> I compare this with microMIPS32 manual [1] Table 6.5, but I still
> don't understand why they're encoded in such way. The comment says
> "bits 13..12 for 0x01", I can roughly understand the enum list
> bits 13..12 here, but what "for 0x01" exactly means?

Please refer to the following document.

MIPS® Architecture for Programmers VolumeIV-e: The MIPS® DSP 
Application-Specific Extension to the microMIPS32™ Architecture

http://www.mips.com/secure-download/index.dot?product_name=/auth/MD00764-2B-microMIPS32DSP-AFP-02.34.pdf

-Eric