Intel x86 Floating-Point Registers

TotalView displays the x86 floating-point registers in the Stack Frame Pane of the Process Window. The next table describes how TotalView treats each floating-point register, and the actions you can take with each register.


Register	Description	Data Type	Edit	Dive	Specify in Expression
ST0	ST(0)	$extended	yes	yes	$st0
ST1	ST(1)	$extended	yes	yes	$st1
ST2	ST(2)	$extended	yes	yes	$st2
ST3	ST(3)	$extended	yes	yes	$st3
ST4	ST(4)	$extended	yes	yes	$st4
ST5	ST(5)	$extended	yes	yes	$st5
ST6	ST(6)	$extended	yes	yes	$st6
ST7	ST(7)	$extended	yes	yes	$st7
FPCR	Floating-point control register	$int	yes	no	$fpcr
FPSR	Floating-point status register	$int	no	no	$fpsr
FPTAG	Tag word	$int	no	no	$fptag
FPIOFF	Instruction offset	$int	no	no	$fpioff
FPISEL	Instruction selector	$int	no	no	$fpisel
FPDOFF	Data offset	$int	no	no	$fpdoff
FPDSEL	Data selector	$int	no	no	$fpdsel
MXCSR	SSE status and control	$int	yes	no	$mxcsv
MXCSR_MASK	MXCSR mask	$int	no	no	$mxcsr_ mask
XMM0_L ... XMM7_L	Streaming SIMD -Extension: left half	$long long	yes	yes	$xmm0_l ... $xmm7_l
XMM0_H ... XMM7_H	Streaming SIMD -Extension: right half	$long long	yes	yes	$xmm0_h ... $xmm7_h

NOTE >> The Pentium III and 4 have 8 128-bit registers that are used by SSE and SSE2 instructions. TotalView displays these as 16 64-bit registers. These registers can be used in the following ways: 16 bytes, 8 words, 2 long longs, 4 floating point, 2 double, or a single 128-bit value. TotalView shows each of these hardware registers as two $long long registers. To change the type, dive and then edit the type in the data window to be an array of the type you wish. For example, cast it to “$char[16]”, “$float[4], and so on.