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Volume 1, Part 1: Floating-point Programming Model
1:107
performance on implementations that do not implement denormal handling in
hardware. When the Flush-to-Zero mode is enabled, floating-point exception software
assist traps will not occur when producing tiny results.
5.4.4
Integer Invalid Operations
Floating-point to integer conversions which are invalid (in the IEEE sense) signal an
Invalid Operation Floating-Point Exception fault. If the IEEE Invalid Operation trap is
disabled, then the largest magnitude negative integer is the result, even for unsigned
integer operations.
5.4.5
Definition of Arithmetic Operations
Arithmetic operations are those that compute on the operands by treating each
operand’s encoding as a value, whereas non-arithmetic operations perform bit
manipulations on the input operands without regard to the value represented by the
encoding (except for NaTVal detection). Non-arithmetic instructions do not cause
Floating-point Exception faults or traps, but can cause the Disabled Floating-point
Register fault.
5.4.6
Definition and Propagation of NaNs
Signaling NaNs have a zero in the most significant fractional bit of the significand. Quiet
NaNs have a one in the most significant fractional bit of the significand. This definition
of signaling and quiet NaNs easily preserves “NaNness” when converting between
different precisions. When propagating NaNs in operations that have more than one
NaN operand, the result NaN is chosen from one of the operand NaNs in the following
priority based on register encoding fields: first
f4,
then
f2
, and lastly
f3
.
5.4.7
IEEE Standard Mandated Operations Deferred to Software
The following IEEE mandated operations will be implemented in software:
• String to floating-point conversion
• Floating-point to string conversion
• Divide (with help from
frcpa
or
fprcpa
instruction)
• Square root (with help from
frsqrta
or
fprsqrta
instruction)
• Remainder (with help from
frcpa
or
fprcpa
instruction)
• Floating-point to integer valued floating-point conversion
• Correctly wrapping the exponent for single, double, and double-extended overflow
and underflow values, as recommended by the IEEE standard
5.4.8
Additions beyond the IEEE Standard
• The fused multiply and add (
fma
,
fms
,
fnma
,
fpma
,
fpms
,
fpnma
) operations enable
efficient software divide, square root, and remainder algorithms.
• The extended range of the 17-bit exponent in the register format allows simplified
implementation of many basic numeric algorithms by the careful numeric
programmer.
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Страница 1: ......
Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 12: ...1 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I Application Architecture Guide ...
Страница 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Страница 230: ......
Страница 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
Страница 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
Страница 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Страница 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Страница 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Страница 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Страница 891: ......
Страница 941: ...3 42 Volume 3 Instruction Reference cmp illegal_operation_fault PR p1 0 PR p2 0 Interruptions Illegal Operation fault ...
Страница 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Страница 1296: ......
Страница 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...