Volume 4: Base IA-32 Instruction Reference
4:133
FINIT/FNINIT—Initialize Floating-point Unit
Description
Sets the FPU control, status, tag, instruction pointer, and data pointer registers to their
default states. The FPU control word is set to 037FH (round to nearest, all exceptions
masked, 64-bit precision). The status word is cleared (no exception flags set, TOP is set
to 0). The data registers in the register stack are left unchanged, but they are all
tagged as empty (11B). Both the instruction and data pointers are cleared.
The FINIT instruction checks for and handles any pending unmasked floating-point
exceptions before performing the initialization; the FNINIT instruction does not.
Operation
FPUControlWord
037FH;
FPUStatusWord
0;
FPUTagWord
FFFFH;
FPUDataPointer
0;
FPUInstructionPointer
0;
FPULastInstructionOpcode
0;
FPU Flags Affected
C0, C1, C2, C3 cleared to 0.
Floating-point Exceptions
None.
Additional Itanium System Environment Exceptions
Itanium Reg Faults Disabled FP Register Fault if PSR.dfl is 1.
Protected Mode Exceptions
#NM
EM or TS in CR0 is set.
Real Address Mode Exceptions
#NM
EM or TS in CR0 is set.
Virtual 8086 Mode Exceptions
#NM
EM or TS in CR0 is set.
Opcode
Instruction
Description
9B DB E3
FINIT
Initialize FPU after checking for pending unmasked
floating-point exceptions.
DB E3
FNINIT
Initialize FPU without checking for pending unmasked
floating-point exceptions.
Summary of Contents for ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Page 1: ......
Page 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Page 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Page 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Page 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Page 230: ......
Page 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Page 380: ...2 132 Volume 2 Part 1 Interruptions ...
Page 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Page 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Page 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Page 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Page 808: ...2 560 Volume 2 Part 2 Context Management ...
Page 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Page 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Page 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Page 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Page 891: ......
Page 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Page 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Page 1296: ......
Page 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Page 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Page 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Page 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Page 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Page 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...