From 2c9ee52c3726b43fda9f68dbbcad069b3c2e874c Mon Sep 17 00:00:00 2001 From: Gabe Black Date: Mon, 17 Aug 2009 20:25:14 -0700 Subject: [PATCH] X86: Implement a microop that compares fp values and writes to rflags. --- src/arch/x86/isa/microops/mediaop.isa | 55 +++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/src/arch/x86/isa/microops/mediaop.isa b/src/arch/x86/isa/microops/mediaop.isa index 1bd99db3a..75a4c9468 100644 --- a/src/arch/x86/isa/microops/mediaop.isa +++ b/src/arch/x86/isa/microops/mediaop.isa @@ -1342,4 +1342,59 @@ let {{ } FpDestReg.uqw = result; ''' + + class Mcmpf2rf(MediaOp): + def __init__(self, src1, src2,\ + size = None, destSize = None, srcSize = None, ext = None): + super(Mcmpf2rf, self).__init__("InstRegIndex(0)", src1,\ + src2, size, destSize, srcSize, ext) + code = ''' + union floatInt + { + float f; + uint32_t i; + }; + union doubleInt + { + double d; + uint64_t i; + }; + + assert(srcSize == destSize); + assert(srcSize == 4 || srcSize == 8); + int size = srcSize; + int sizeBits = size * 8; + + double arg1, arg2; + uint64_t arg1Bits = bits(FpSrcReg1.uqw, sizeBits - 1, 0); + uint64_t arg2Bits = bits(FpSrcReg2.uqw, sizeBits - 1, 0); + if (size == 4) { + floatInt fi; + fi.i = arg1Bits; + arg1 = fi.f; + fi.i = arg2Bits; + arg2 = fi.f; + } else { + doubleInt di; + di.i = arg1Bits; + arg1 = di.d; + di.i = arg2Bits; + arg2 = di.d; + } + + // ZF PF CF + // Unordered 1 1 1 + // Greater than 0 0 0 + // Less than 0 0 1 + // Equal 1 0 0 + // OF = SF = AF = 0 + ccFlagBits = ccFlagBits & ~(OFBit | SFBit | AFBit | + ZFBit | PFBit | CFBit); + if (isnan(arg1) || isnan(arg2)) + ccFlagBits = ccFlagBits | (ZFBit | PFBit | CFBit); + else if(arg1 < arg2) + ccFlagBits = ccFlagBits | CFBit; + else if(arg1 == arg2) + ccFlagBits = ccFlagBits | ZFBit; + ''' }}; -- 2.30.2