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Volume 4: Base IA-32 Instruction Reference
FICOM/FICOMP—Compare Integer
Description
Compares the value in ST(0) with an integer source operand and sets the condition
code flags C0, C2, and C3 in the FPU status word according to the results (see table
below). The integer value is converted to extended-real format before the comparison
is made.
These instructions perform an “unordered comparison.” An unordered comparison also
checks the class of the numbers being compared. If either operand is a NaN or is in an
undefined format, the condition flags are set to “unordered.”
The sign of zero is ignored, so that -0.0 = +0.0.
The FICOMP instructions pop the register stack following the comparison. To pop the
register stack, the processor marks the ST(0) register empty and increments the stack
pointer (TOP) by 1.
Operation
CASE (relation of operands) OF
ST(0) > SRC:
C3, C2, C0
000;
ST(0) < SRC:
C3, C2, C0
001;
ST(0) = SRC:
C3, C2, C0
100;
Unordered:
C3, C2, C0
111;
ESAC;
IF instruction = FICOMP
THEN
PopRegisterStack;
FI;
FPU Flags Affected
C1
Set to 0 if stack underflow occurred; otherwise, set to 0.
C0, C2, C3
See table on previous page.
Opcode
Instruction
Description
DE /2
FICOM
m16int
Compare ST(0) with
m16int
DA /2
FICOM
m32int
Compare ST(0) with
m32int
DE /3
FICOMP
m16int
Compare ST(0) with
m16int
and pop stack register
DA /3
FICOMP
m32int
Compare ST(0) with
m32int
and pop stack register
Condition
C3
C2
C0
ST(0) > SRC
0
0
0
ST(0) < SRC
0
0
1
ST(0) = SRC
1
0
0
Unordered
1
1
1
Содержание ITANIUM ARCHITECTURE
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Страница 7: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 199: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 269: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 270: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 273: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 288: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 352: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 368: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 373: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 589: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 590: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 591: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 603: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...
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