Hi,
My driver uses SSE instructions to do some floating point calc and it
appears that the xmm registers within WinDbg are not being updated correctly
here is any example of using the xorps xmm1,xmm1 instruction to zero the
xmm1 register :
kd> rX
xmm0=0 1.66755e-043 1.37327e-043 1.30321e-043
xmm1=3.57331e-043 0 0 0
xmm2=0 1.66755e-043 1.37327e-043 1.30321e-043
xmm3=3.57331e-043 0 0 0
xmm4=0 1.66755e-043 1.37327e-043 1.30321e-043
xmm5=-4.42013e-038 0 0 0
xmm6=1 -4.44817e-008 30553.6 -408371
xmm7=-1.05944e+035 -1.05942e+035 1.4013e-045 0.544361
MyDrv!SSECode+2fa:
bfa4d3ff 0f57c9 xorps xmm1,xmm1
kd> p
MyDrv!SSECode+2fd:
bfa4d402 0f28d6 movaps xmm2,xmm6
kd> rX
xmm0=0 1.66755e-043 1.37327e-043 1.30321e-043
xmm1=3.57331e-043 0 0 0
xmm2=0 1.66755e-043 1.37327e-043 1.30321e-043
xmm3=3.57331e-043 0 0 0
xmm4=0 1.66755e-043 1.37327e-043 1.30321e-043
xmm5=-4.42013e-038 0 0 0
xmm6=1 -4.44817e-008 30553.6 -408371
xmm7=-1.05944e+035 -1.05942e+035 1.4013e-045 0.544361
As you can see the xmm1 register has a not zero value after the xorps
xmm1,xmm1 instruction.
Is this a bug in WinDbg?
Yours
Roger
Roger Coote,
Senior Design Engineer
PowerVR Technologies, A Division of Imagination Technologies Ltd
Home Park Estate, Kings Langley, Hertfordshire, WD4 8LZ, UK
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