Volume 4: Base IA-32 Instruction Reference
4:97
F2XM1—Compute 2
x
-1
Description
Calculates the exponential value of 2 to the power of the source operand minus 1. The
source operand is located in register ST(0) and the result is also stored in ST(0). The
value of the source operand must lie in the range -1.0 to +1.0. If the source value is
outside this range, the result is undefined.
The following table shows the results obtained when computing the exponential value
of various classes of numbers, assuming that neither overflow nor underflow occurs:
Values other than 2 can be exponentiated using the following formula:
x
y
= 2
(y
log
2
x)
Operation
ST(0)
(2
ST(0)
1);
FPU Flags Affected
C1
Set to 0 if stack underflow occurred.
Indicates rounding direction if the inexact-result exception (#P) is
generated: 0 = not roundup; 1 = roundup.
C0, C2, C3
Undefined.
Additional Itanium System Environment Exceptions
Itanium Reg Faults Disabled FP Register Fault if PSR.dfl is 1, NaT Register Consumption
Abort.
Floating-point Exceptions
#IS
Stack underflow occurred.
#IA
Source operand is an SNaN value or unsupported format.
#D
Result is a denormal value.
#U
Result is too small for destination format.
#P
Value cannot be represented exactly in destination format.
Opcode
Instruction
Description
D9 F0
F2XM1
Replace ST(0) with (2
ST(0)
- 1)
ST(0) SRC
ST(0) DEST
-1.0 to
0
0.5 to
0
0
0
0
+0
+0 to +1.0
+0 to 1.0
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 ...
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