SCL Reference: loop Statement

TheSCLloop statement provides looping capability.

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loop   scl statements   exit when booleanExpression     // optionalend loop;

The boolean expression is what you would expect it to be. Here are a few examples:

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//infinite loop (no exit when)loop   RD1 <= '0';   wait on RD1;end loop;//clock until pc == foo labelloop   RD0 <= '0';   wait 4 ic;   RD0 <= '1';   wait 4 ic;   exit when PC == foo;end loop;//unadorned exit (yeah this is contrived!)loop   AN1 <= 3500 mv;   exit;             // unconditional exitend loop;

Note that a loop can have more than one exit when condition:

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//multiple exit conditionsloop   wait on RD1;   RD0 <= '0';   exit when STATUS.Z == 0;   exit when RD2 == '0';end loop;