SPARC Assembly Language Reference Manual

2.3 Lexical Features

This section describes the lexical features of the assembler syntax.

2.3.1 Case Distinction

Uppercase and lowercase letters are distinct everywhere except in the names of special symbols. Special symbol names have no case distinction.


A comment is preceded by an exclamation mark character (!); the exclamation mark character and all following characters up to the end of the line are ignored. C language-style comments (``/*…*/'') are also permitted and may span multiple lines.

2.3.3 Labels

A label is either a symbol or a single decimal digit n (0…9). A label is immediately followed by a colon ( : ).

Numeric labels may be defined repeatedly in an assembly file; normal symbolic labels may be defined only once.

A numeric label n is referenced after its definition (backward reference) as nb, and before its definition (forward reference) as nf.

2.3.4 Numbers

Decimal, hexadecimal, and octal numeric constants are recognized and are written as in the C language. However, integer suffixes (such as L) are not recognized.

For floating-point pseudo-operations, floating-point constants are written with 0r or 0R (where r or R means REAL) followed by a string acceptable to atof(3); that is, an optional sign followed by a non-empty string of digits with optional decimal point and optional exponent.

The special names 0rnan and 0rinf represent the special floating-point values Not-A-Number (NaN) and INFinity. Negative Not-A-Number and Negative INFinity are specified as 0r-nan and 0r-inf.

Note –

The names of these floating-point constants begin with the digit zero, not the letter “O.”

2.3.5 Strings

A string is a sequence of characters quoted with either double-quote mark (") or single-quote mark (') characters. The sequence must not include a newline character. When used in an expression, the numeric value of a string is the numeric value of the ASCII representation of its first character.

The suggested style is to use single quote mark characters for the ASCII value of a single character, and double quote mark characters for quoted-string operands such as used by pseudo-ops. An example of assembly code in the suggested style is:

add %g1,'a'-'A',%g1 ! g1 + ('a' - 'A') --> g1 

The escape codes described in Table 2–1, derived from ANSI C, are recognized in strings.

Table 2–1

Escape Code 







Form feed  


Newline (line feed)  


Carriage return  


Horizontal tab  


Vertical tab  


Octal value nnn


Hexadecimal value nn...

2.3.6 Symbol Names

The syntax for a symbol name is:

{ letter | _ | $ | . }   { letter | _ | $ | . | digit }* 

In the above syntax:

2.3.7 Special Symbols - Registers

Special symbol names begin with a percentage sign (%) to avoid conflict with user symbols. Table 2–2 lists these special symbol names.

Table 2–2

Symbol Object 



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 = %o6 = %r14)

Frame-pointer register 


(%fp = %i6 = %r30)

Floating-point registers 

%f0 … %f31


Floating-point status register 



Front of floating-point queue 



Coprocessor registers 

%c0 … %c31


Coprocessor status register 



Coprocessor queue 



Program status register 



Trap vector base address register 



Window invalid mask 



Y register 



Unary operators 


Extracts least significant 10 bits 



Extracts most significant 22 bits 



Used only in Sun compiler-generated code. 



Used only in Sun compiler-generated code. 

Ancillary state registers 

%asr1 … %asr31


There is no case distinction in special symbols; for example,


is equivalent to


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

2.3.8 Operators and Expressions

The operators described in Table 2–3 are recognized in constant expressions.

Table 2–3





Integer addition 


(No effect) 


Integer subtraction 

2's Complement  

Integer multiplication 


1's Complement 

Integer division 


Extract least significant 10 bits as computed by: (address & 0x3ff) 



Extract most significant 22 bits as computed by: (address >>10) 

Exclusive OR



Used in Sun compiler-generated code only to instruct the assembler to generate specific relocation information for the given expression. 


Left shift 



Used in Sun compiler-generated code only to instruct the assembler to generate specific relocation information for the given expression. 


Right shift 



Bitwise AND



Bitwise OR



Since these operators have the same precedence as in the C language, put expressions in parentheses to avoid ambiguity.

To avoid confusion with register names or with the %hi, %lo, %r_disp32/64, or %r_plt32/64 operators, the modulo operator % must not be immediately followed by a letter or digit. The modulo operator is typically followed by a space or left parenthesis character.

2.3.9 SPARC V9 Operators and Expressions

The following V9 64-bit operators and expressions in Table 2–4 ease the task of converting from V8/V8plus assembly code to V9 assembly code.

Table 2–4





(address) >> 42 

Extract bits 42-63 of a 64-bit word 


((address) >> 32) & 0x3ff 

Extract bits 32-41 of a 64-bit word 


(((address) >> 10) & 0x3fffff) 

Extract bits 10-31 of a 64-bit word 

For example:::

sethi %hh (address), %l1
or %l1, %hm (address), %l1
sethi %lm (address), %12
or %12, %lo (address), %12
sllx %l1, 32, %l1
or %l1, %12, %l1

The V9 high 32-bit operators and expressions are identified in Table 2–5.

Table 2–5





((((address) ^ 0xffffffffffffffff >> 10) &0x4fffff) 

Invert every bit and extract bits 10-31 


((address) & 0x3ff | 0x1c00 

Extract bits 0-9 and sign extend that to 13 bits 

For example:

%sethi %hix (address), %l1
or %l1, %lox (address), %l1

The V9 low 44-bit operators and expressions are identified in Table 2–6.

Table 2–6





((address) >> 22) 

Extract bits 22-43 of a 64-bit word 


((address) >> 12) & 0x3ff 

Extract bits 12-21 of a 64-bit word 


(address) & 0xfff 

Extract bits 0-11 of a 64-bit word 

For example::

%sethi %h44 (address), %l1
or %l1, %m44 (address), %l1
sllx %l1, 12, %l1
or %l1, %144 (address), %l1