4:100
Volume 4: Base IA-32 Instruction Reference
FADD/FADDP/FIADD—Add
Description
Adds the destination and source operands and stores the sum in the destination
location. The destination operand is always an FPU register; the source operand can be
a register or a memory location. Source operands in memory can be in single-real,
double-real, word-integer, or short-integer formats.
The no-operand version of the instruction adds the contents of the ST(0) register to the
ST(1) register. The one-operand version adds the contents of a memory location (either
a real or an integer value) to the contents of the ST(0) register. The two-operand
version, adds the contents of the ST(0) register to the ST(
i
) register or vice versa. The
value in ST(0) can be doubled by coding:
FADD ST(0), ST(0);
The FADDP instructions perform the additional operation of popping the FPU register
stack after storing the result. To pop the register stack, the processor marks the ST(0)
register as empty and increments the stack pointer (TOP) by 1. (The no-operand
version of the floating-point add instructions always results in the register stack being
popped. In some assemblers, the mnemonic for this instruction is FADD rather than
FADDP.)
The FIADD instructions convert an integer source operand to extended-real format
before performing the addition.
The table on the following page shows the results obtained when adding various classes
of numbers, assuming that neither overflow nor underflow occurs.
When the sum of two operands with opposite signs is 0, the result is +0, except for the
round toward
mode, in which case the result is
0. When the source operand is an
integer 0, it is treated as a +0.
When both operand are infinities of the same sign, the result is
of the expected sign.
If both operands are infinities of opposite signs, an invalid-operation exception is
generated.
Opcode
Instruction
Description
D8 /0
FADD
m32 real
Add
m32real
to ST(0) and store result in ST(0)
DC /0
FADD
m64real
Add
m64real
to ST(0) and store result in ST(0)
D8 C0+i
FADD ST(0), ST(i)
Add ST(0) to ST(i) and store result in ST(0)
DC C0+i
FADD ST(i), ST(0)
Add ST(i) to ST(0) and store result in ST(
i
)
DE C0+i
FADDP ST(i), ST(0)
Add ST(0) to ST(i), store result in ST(
i
), and pop the register
stack
DE C1
FADDP
Add ST(0) to ST(1), store result in ST(1), and pop the register
stack
DA /0
FIADD
m32int
Add
m32int
to ST(0) and store result in ST(0)
DE /0
FIADD
m16int
Add
m16int
to ST(0) and store result in ST(0)
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 ...