howto_sse2.lyx

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\layout Standard


\begin_inset Graphics
	filename images_mmx/NewPCMP.gif
	lyxscale 65
	scale 55
	keepAspectRatio

\end_inset 


\layout Itemize

PCMPEQD Packed Compare for Equal, Doubleword
\layout Standard

Latency : 2 Throughput : 1
\layout Standard

Purpose:
\layout Standard

PCMPEQD compares the doublewords in the destination operand to the corresponding
 doublewords in the source operand.
 If the data elements are equal, the corresponding data element in destination
 is set to all ones.
 If they are not equal, the corresponding data element is set to all zeros.
 
\layout Itemize

PCMPEQW Packed Compare for Equal, Word
\layout Standard

Latency : 2 Throughput : 1
\layout Standard

Purpose:
\layout Standard

PCMPEQ compares the words in the destination operand to the corresponding
 words in the source operand.
 If the data elements are equal, the corresponding data element in the destinati
on register is set to all ones.
 If they are not equal, the corresponding data element is set to all zeros.
 
\layout Itemize

PCMPGTB Packed Compare for Greater Than, Byte
\layout Standard

Latency : 2 Throughput : 1
\layout Standard

Purpose:
\layout Standard

PCMPGTB compares the signed bytes in the destination operand to the signed
 bytes in the source operand.
 If the signed data elements in destination are greater than those in the
 source operand, the corresponding data element in the destination operand
 is set to all ones.
 Otherwise, it is set to all zeros.
\layout Itemize

PCMPGTD Packed Compare Greater Than, Doubleword
\layout Standard

Latency : 2 Throughput : 1
\layout Standard

Purpose:
\layout Standard

PCMPGTD compares the signed doublewords in the destination operand to the
 signed doublewords in the source operand.
 If the signed data elements in destination are greater than those in the
 source operand, the corresponding data element in the destination operand
 is set to all ones.
 Otherwise, it is set to all zeros.
 
\layout Itemize

PCMPGTW Packed Compare for Greater Than, Word
\layout Standard

Latency : 2 Throughput : 1
\layout Standard

Purpose:
\layout Standard

PCMPGTBW compares the signed words in the destination operand to the signed
 words in the source operand.
 If the signed data elements in destination are greater than those in the
 source operand, the corresponding data element in the destination operand
 is set to all ones.
 Otherwise, it is set to all zeros.
\layout Standard

SSE-
\layout Itemize

CMPPS xmm1,xmm2/mem128,imm8
\layout Standard

Latency : 4 Throughput : 2
\layout Standard

Purpose:
\layout Standard

Compares the two packed single-precision FP values in the source and destination
 operands, and returns the result of the comparison in the destination register.
 The result of each comparison is a quadword mask of all 1s (comparison
 true) or all 0s (comparison false).
 The destination is an XMM register.
 The source can be either an XMM register or a 128-bit memory location.
\layout Standard

The third operand is an 8-bit immediate value, of which the low 3 bits define
 the type of comparison.
 The "Condition Predicates" are:
\layout Standard
\align center 

\begin_inset  Tabular
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<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

VALUE
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

COMPARISION
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

0
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

EQUAL
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

1
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

LESS THAN
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

2
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

LESS THAN OR EQUAL
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

3
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

UNORDERED
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

4
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

NOT EQUAL
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

5
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

NOT LESS THAN
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

6
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

NOT LESS THAN EQUAL
\end_inset 
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

7
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

ORDERED
\end_inset 
</cell>
</row>
</lyxtabular>

\end_inset 


\layout Itemize

CMPSS xmm1,xmm2/mem32,imm8 
\layout Standard

Latency : 4 Throughput : 2
\layout Standard

Purpose:
\layout Standard

Compare single precision floating point value in lower 32 bits and return
 mask as result
\layout Itemize

COMISS xmm1,xmm2/mem64
\layout Standard

Latency : 6 Throughput : 2
\layout Standard

Purpose:
\layout Standard

COMISS compares the low-order single-precision FP value in the two source
 operands.
 ZF, PF, and CF are set according to the result.
 OF, AF, and AF are cleared.
 The unordered result is returned if either source is a NaN (QNaN or SNaN).
 The destination operand is an XMM register.
 The source can be either an XMM register or a memory location.
\layout Standard

The flags are set according to the following rules:
\layout Standard
\align center 

\begin_inset  Tabular
<lyxtabular version="3" rows="5" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" width="0">
<column alignment="center" valignment="top" leftline="true" width="0">
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<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

Result
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

Flags
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

Values
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

UNORDERED
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

ZF,PF,CF
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

111
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

GREATER THAN
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

ZF,PF,CF
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

000
\end_inset 
</cell>
</row>
<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

LESS THAN
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

ZF,PF,CF
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

001
\end_inset 
</cell>
</row>
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

EQUAL
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text

\layout Standard

ZF,PF,CF
\end_inset 
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text

\layout Standard

100
\end_inset 
</cell>
</row>
</lyxtabular>

\end_inset 


\layout Itemize

UCOMISS xmm1,xmm2/mem32
\layout Standard

Latency : 6 Throughput : 2
\layout Standard

Purpose:
\layout Standard

UCOMISS compares the 32-bit floating-point numbers in the lowest part of
 the two operands, and sets the CPU flags appropriately.
 UCOMISS differs from COMISS in that it signals an invalid numeric exeception
 only if an operand is an sNaN, whereas COMISS does so also if an operand
 is a qNaN.
 
\layout Standard

SSE2-
\layout Itemize

CMPPD xmm, xmm 
\layout Standard

Latency: 4 Throughput: 2 
\layout Standard

Purpose:
\layout Standard

Compare double precision floating point values and return masks as result
\layout Itemize

CMPSD xmm, xmm, imm8 
\layout Standard

Latency: 4 Throughput: 2
\layout Standard

Purpose:
\layout Standard

Compare double precision floating point value in lower 64 bits and return
 mask as result
\layout Itemize

COMISD xmm, xmm 
\layout Standard

Latency: 6 Throughput: 2
\layout Standard

Purpose:
\layout Standard

Compare double precision floating point value in lower 64 bits and return
 result in flag register
\layout Itemize

UCOMISD xmm, xmm 
\layout Standard

Latency: 6 Throughput: 2
\layout Standard

Purpose:
\layout Standard

Compare unordered double precision floating point value in lower 64 bits
 and return result in flag register
\layout Subsection

Conversion Instructions
\layout Standard

MMX-
\layout Standard

Usage: instruction destination, source 
\layout Standard

Destination: MMX register.
 
\layout Standard

Source: MMX register or 64-bit memory operand.
\layout Itemize

PACKSSDW Pack Doublewords into Words (Signed with Saturation)
\layout Standard

Latency : 2 Throughput : 1
\layout Standard

Purpose:
\layout Standard

PACKSSDW packs two signed doublewords from the source operand and two signed