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use lang:bs;
use lang:bs:macro;
use core:lang;
use core:asm;
class RepeatStmt extends Expr {
private Expr times;
private Expr body;
init(SrcPos pos, Block parent, Expr times, Expr body) {
init(pos) {
times = expectCastTo(times, named{Nat}, parent.scope);
body = body;
}
}
void code(CodeGen gen, CodeResult result) : override {
// Compute the number of iterations.
VarInfo counter = gen.createVar(named{Nat});
times.code(gen, CodeResult(named{Nat}, counter));
// Top of the loop.
Label loopStart = gen.l.label();
gen.l << loopStart;
// Check number of iterations.
Label loopEnd = gen.l.label();
gen.l << cmp(counter.v, natConst(0));
gen.l << jmp(loopEnd, CondFlag:ifEqual);
// Evaluate the body.
body.code(gen, CodeResult());
// Decrement the counter and jump to the start.
gen.l << sub(counter.v, natConst(1));
gen.l << jmp(loopStart);
gen.l << loopEnd;
}
}
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