Datasheet

Floating-point Support
ARM DUI 0067D Copyright © 1999-2001 ARM Limited. All rights reserved. 5-7
5.2.4 Floating-point comparisons
The routines in Table 5-4 perform comparisons between floating-point numbers.
Table 5-4 Floating-point comparison routines
Function Argument types Result type Condition tested
_fcmpeq 2 float Flags, EQ/NE
x equal to y
a
_fcmpge 2 float Flags, HS/LO
x greater than or equal to y
a,b
_fcmple 2 float Flags, HI/LS
x less than or equal to y
a,b
_feq 2 float Boolean x equal to y
_fneq 2 float Boolean x not equal to y
_fgeq 2 float Boolean
x greater than or equal to y
b
_fgr 2 float Boolean
x greater than y
b
_fleq 2 float Boolean
x less than or equal to y
b
_fls 2 float Boolean
x less than y
b
_dcmpeq 2 double Flags, EQ/NE
x equal to y
a
_dcmpge 2 double Flags, HS/LO
x greater than or equal to y
a,b
_dcmple 2 double Flags, HI/LS
x less than or equal to y
a,b
_deq 2 double Boolean x equal to y
_dneq 2 double Boolean x not equal to y
_dgeq 2 double Boolean
x greater than or equal to y
b
_dgr 2 double Boolean
x greater than y
b
_dleq 2 double Boolean
x less than or equal to y
b
_dls 2 double Boolean
x less than y
b
a. Returns results in the ARM condition flags. This is efficient in assembly language, because you can directly follow a call to
the function with a conditional instruction, but it means there is no way to use these functions from C. These functions are not
declared in
rt_fp.h .
b. Causes an Invalid Operation exception if either argument is a NaN, even a quiet NaN. Other functions only cause Invalid
Operation if an argument is an SNaN. QNaNs return not equal when compared to anything, including other QNaNs (so
comparing a QNaN to the same QNaN still returns not equal).