Red Hat ENTERPRISE LINUX 4 Manual page 204

196
N
Same as , except that it verifies that bits that are not in the lower 32-bit range are all zero.
K
Must be used instead of
O
The constant 4096
G
Floating-point zero
H
Signed 13-bit constant, sign-extended to 32 or 64 bits
Q
Floating-point constant whose integral representation can be moved into an integer register
using a single sethi instruction
R
Floating-point constant whose integral representation can be moved into an integer register
using a single mov instruction
S
Floating-point constant whose integral representation can be moved into an integer register
using a high/lo_sum instruction sequence
T
Memory address aligned to an 8-byte boundary
U
Even register
W
Memory address for
TMS320C3x/C4x--
c4x.h
a
Auxiliary (address) register (ar0-ar7)
b
Stack pointer register (sp)
c
Standard (32-bit) precision integer register
f
Extended (40-bit) precision register (r0-r11)
Chapter 6. Extensions to the C Language Family
for modes wider than
K
constraint registers.
e
SImode