MSC100ABIRM Motorola / Freescale Semiconductor, MSC100ABIRM Datasheet - Page 79

• Manufacturer Part Number: MSC100ABIRM
• Description: SC100 Application Binary Interface Reference Manual
• Manufacturer: Motorola / Freescale Semiconductor

Assembler Directives
6.2.6.2 Symbol Names
Symbol names can be from one to 4000 characters long. The first character of a symbol must be alphabetic
(upper or lower case); any remaining characters can be either alphanumeric (A-Z, a-z, 0-9) or the
underscore character (_). Upper and lower case letters in symbols are considered distinct unless the IC
option is in effect. Symbol names and other identifiers beginning with a ‘.’ are legal but reserved for the
system.
a) Valid Symbol Names
b) Invalid Symbol Names
loop_1
1_loop
ENTRY
loop.e
a_B_c
Certain identifiers are reserved by the assembler and cannot be used. These identifiers are the upper- or
lower-case name of any SC140 DSP core processor register.
6.2.6.3 Strings
One or more ASCII characters enclosed by single quotes (') constitute a literal ASCII string. In order to
specify an apostrophe within a literal string, two consecutive apostrophes must appear where the single
apostrophe is intended. Strings are used as operands for some assembler directives and also can be used to
a limited extent in expressions.
A string may also be enclosed in double quotes (") in which case any DEFINE directive symbols contained
in the string would be expanded. The double quote should be used with care inside macros since it is used
as a dummy argument string operator. In that case, the macro concatenation operator can be used to escape
the double-quoted string if desired.
Two strings separated by the string concatenation operator (++) will be recognized by the assembler as
equivalent to the concatenation of the two strings. For example, the following two strings are equivalent:
'ABC'++'DEF' = 'ABCDEF'
The assembler has a substring extraction capability using the square brackets ([ ]). Refer to the following
example:
['abcdefg',1,3] = 'bcd'
Substrings may be used wherever strings are valid and can be nested. There are also functions for
determining the length of a string and the position of one string within another.
SC100 Application Binary Interface
6-5
Preliminary (April 2000)