From f5b9217531dac37451845cd83dfd30e4cc1053b4 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 8 Dec 2016 12:22:33 +0100 Subject: [PATCH] x86emul: simplify {,i}{mul,div} fix Commit 75066cd4ea ("x86emul: fix {,i}mul and {,i}div") can be had with less code: Simply do the destination register override depending on DstEax being in effect (the four other ModRM.reg encoded operations of these two opcodes all use DstMem). Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper --- xen/arch/x86/x86_emulate/x86_emulate.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c index 22b8dc8900..d66ce7ac1c 100644 --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -4104,6 +4104,8 @@ x86_emulate( break; case 0xf6 ... 0xf7: /* Grp3 */ + if ( (d & DstMask) == DstEax ) + dst.reg = (unsigned long *)&_regs.eax; switch ( modrm_reg & 7 ) { unsigned long u[2], v; @@ -4118,7 +4120,6 @@ x86_emulate( emulate_1op("neg", dst, _regs.eflags); break; case 4: /* mul */ - dst.reg = (unsigned long *)&_regs.eax; _regs.eflags &= ~(EFLG_OF|EFLG_CF); switch ( dst.bytes ) { @@ -4156,7 +4157,6 @@ x86_emulate( } break; case 5: /* imul */ - dst.reg = (unsigned long *)&_regs.eax; imul: _regs.eflags &= ~(EFLG_OF|EFLG_CF); switch ( dst.bytes ) @@ -4198,7 +4198,6 @@ x86_emulate( } break; case 6: /* div */ - dst.reg = (unsigned long *)&_regs.eax; switch ( src.bytes ) { case 1: @@ -4244,7 +4243,6 @@ x86_emulate( } break; case 7: /* idiv */ - dst.reg = (unsigned long *)&_regs.eax; switch ( src.bytes ) { case 1: -- 2.30.2