Re: [PATCH] powerpc: emulate power5 popcntb instruction
From: Kumar Gala <hidden>
Date: 2006-08-18 19:30:09
From: Kumar Gala <hidden>
Date: 2006-08-18 19:30:09
On Aug 18, 2006, at 2:05 PM, Arnd Bergmann wrote:
On Friday 18 August 2006 20:11, Will Schmidt wrote:quoted
+#define INST_POPCNTB 0x7c0000f4 +quoted
+ /* Emulate the popcntb (Population Count Bytes) instruction. */ + if ((instword & INST_POPCNTB) == INST_POPCNTB) { + return emulate_popcntb_inst(regs, instword); + } +Is that the right check? The other similar traps check against a mask of 0x7c0007fe.
I agree with Arnd here, its better to check with a larger mask to ensure that bits that should be '0' in the minor opcode are. For example, if you had an instruction that was 0x7c0000f7 it would match. - kumar