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X86-64 Instruction Encoding: Difference between revisions

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X86-64 Instruction Encoding (view source)

Revision as of 01:30, 12 April 2014

428 bytes added ,  10 years ago
→‎SIB: Better layout
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{| {{wikitable|background-color: white}}
!style="background-color:#f9f9f9;"| Field
! Field
!style="background-color:#f9f9f9;"| Length
! Length
!style="background-color:#f9f9f9;"| Description
|-
!style="background-color:#f9f9f9; text-align: left; vertical-align: top;"|SIB.scale
|style="vertical-align: SIB.scale |top;"|2 bits||This field indicates the scaling factor of SIB.index, where ''s'' (as used in the tables) equals 2<span style="vertical-align: super;">SIB.scale</span>.
{| {{wikitable}}
! SIB.scale
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|}
|-
!style="background-color:#f9f9f9; text-align: left; vertical-align: top;"|SIB.index
|style="vertical-align: SIB.index|top;"|3 bits||The index register to use. See [[#Registers|Registers]] for the values to use for each of the registers. The REX.X, VEX.~X or XOP.~X field can extend this field with 1 most-significant bit to 4 bits total.
|-
!style="background-color:#f9f9f9; text-align: left; vertical-align: top;"|SIB.base
|style="vertical-align: SIB.base|top;"|3 bits||The base register to use. See [[#Registers|Registers]] for the values to use for each of the registers. The REX.B, VEX.~B or XOP.~B field can extend this field with 1 most-significant bit to 4 bits total.
|}
 
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