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Volume 4: IA-32 SSE Instruction Reference
4:577
MASKMOVQ: Byte Mask Write
(Continued)
Real Address Mode Exceptions:
Interrupt 13 if any part of the operand would lie outside of the effective address space
from 0 to 0FFFFH;
#UD if CR0.EM = 1; #NM if TS bit in CR0 is set; #MF if there is a
pending FPU exception.
Virtual 8086 Mode Exceptions:
Same exceptions as in Real Address Mode; #AC for unaligned memory reference if the
current privilege level is 3; #PF (fault-code) for a page fault.
Additional Itanium System Environment Exceptions
Itanium Reg Faults Disabled FP Register Fault if PSR.dfl is 1
Comments:
MASKMOVQ can be used to improve performance for algorithms which need to merge
data on a byte granularity.MASKMOVQ should not cause a read for ownership; doing so
generates unnecessary bandwidth since data is to be written directly using the
byte-mask without allocating old data prior to the store. Similar to the SSE
non-temporal store instructions, MASKMOVQ minimizes pollution of the cache
hierarchy. MASKMOVQ implicitly uses weakly-ordered, write-combining stores (WC).
See Section 4.6.1.9, “Cacheability Control Instructions” for further information about
non-temporal stores.
As a consequence of the resulting weakly-ordered memory consistency model, a
fencing operation such as SFENCE should be used if multiple processors may use
different memory types to read/write the same memory location specified by edi.
This instruction behaves identically to MMX technology instructions, in the presence of
x87-FP instructions: transition from x87-FP to MMX technology (TOS=0, FP valid bits
set to all valid).
MASMOVQ ignores the value of CR4.OSFXSR. Since it does not affect the new SSE
state, they will not generate an invalid exception if CR4.OSFXSR = 0.
Summary of Contents for ITANIUM ARCHITECTURE
Page 1: ......
Page 7: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 199: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 352: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 589: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 590: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 591: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 603: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...
Page 604: ......