Texas Instruments TMS320C54x, User Manual

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Assign Character Strings to Substitution Symbols
.loop/.break/.endloop
4-65 Assembler Directives
Syntax
.loop [ well-defined expression]
.break [ well-defined expression]
.endloop
Description Three directives enable you to repeatedly assemble a block of code.
The .loop directive begins a repeatable block of code. The optional expression
evaluates to the loop count (the number of loops to be performed). If there is
no expression, the loop count defaults to 1024, unless the assembler first
encounters a .break directive with an expression that is true (nonzero) or
omitted.
The .break directive is optional, along with its expression. When the expres-
sion is false ( 0 ), the loop continues. When the expression is true ( nonzero),
or omitted, the assembler breaks the loop and assembles the code after the
.endloop directive.
The .endloop directive terminates a repeatable block of code; it executes
when the .break directive is true (nonzero) or when number of loops performed
equals the loop count given by .loop
Example This example illustrates how these directives can be used with the .eval
directive.
1 .eval 0,x
2 COEF .loop
3 .word x*100
4 .eval x+1, x
5 .break x = 6
6 .endloop
1 000000 0000 .word 0*100
1 .eval 0+1, x
1 .break 1 = 6
1 000001 0064 .word 1*100
1 .eval 1+1, x
1 .break 2 = 6
1 000002 00C8 .word 2*100
1 .eval 2+1, x
1 .break 3 = 6
1 000003 012C .word 3*100
1 .eval 3+1, x
1 .break 4 = 6
1 000004 0190 .word 4*100
1 .eval 4+1, x
1 .break 5 = 6
1 000005 01F4 .word 5*100
1 .eval 5+1, x
1 .break 6 = 6