1.3.7 Special Symbols - Registers
Special symbol names begin with a percentage sign (%) to avoid conflict with user symbols. Table 1–2
lists
these special symbol names.
Table 1-2 Special Symbol Names
| | |
|---|
General-purpose registers
| %r0 … %r31
|
|
General-purpose global registers
| %g0 … %g7
| Same as %r0 … %r7
|
General-purpose out registers
| %o0 … %o7
| Same as %r8 … %r15
|
General-purpose local registers
| %l0 … %l7
| Same as %r16 … %r23
|
General-purpose in registers
| %i0 … %i7
| Same as %r24 … %r31
|
Stack-pointer register
| %sp
| (%sp = %o6 = %r14)
|
Frame-pointer register
| %fp
| (%fp = %i6 = %r30)
|
Floating-point registers
| %f0 … %f31
|
|
Floating-point status register
| %fsr
|
|
Front of floating-point queue
| %fq
|
|
Program status register
| %psr
|
|
Trap vector base address register
| %tbr
|
|
Window invalid mask
| %wim
|
|
Y register
| %y
|
|
Unary operators
| %lo
| Extracts least significant 10 bits
|
|
| %hi
| Extracts most significant 22 bits
|
|
| %r_disp32
| Used only in
Solaris Studio
compiler-generated code.
|
|
| %r_plt32
| Used only in
Solaris Studio
compiler-generated code.
|
Ancillary state registers
| %asr1 … %asr31
|
|
|
There is no case distinction in special symbols; for example,
%PSR
is equivalent to
%psr
The suggested style is to use lowercase letters.
The lack of case distinction allows for the use
of non-recursive preprocessor substitutions, for example:
#define psr %PSR
The special symbols %hi and %lo are
true unary operators which can be used in any expression and, as other unary
operators, have higher precedence than binary operations. For example:
%hi a+b = (%hi a)+b
%lo a+b = (%lo a)+b
To avoid ambiguity, enclose operands of the %hi or %lo operators in parentheses. For example:
%hi(a) + b