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/* illustrating a multi-pass evaluation */
void pass1_number(number $n) {
Nonfraction(b): { pass1_bitstring(b); }
Fraction(b1, b2): { pass1_bitstring(b1);
pass1_bitstring(b2); }
}
void pass1_bitstring(bitstring $b) {
Oneb: { b->length=1;}
Moreb(bs, *): { pass1_bitstring(bs);
b->length=bs->length+1; }
}
/* pass1_bit omitted, it does nothing */
void pass2_number(number $n) {
Nonfraction(b): { b->scale=0;
pass2_bitstring(b);
n->value= b->value; }
Fraction(b1, b2): { b1->scale=0;
b2->scale= -b2->length;
pass2_bitstring(b1);
pass2_bitstring(b2);
n->value= b1->value+b2->value; }
}
void pass2_bitstring(bitstring $bs) {
Oneb(b): { b->scale= bs->scale;
pass2_bit(b);
bs->value= b->value; }
Moreb(b1, b2): { b2->scale= bs->scale;
b1->scale= bs->scale+1;
pass2_bitstring(b1);
pass2_bit(b2);
bs->value= b1->value + b2->value; }
}
void pass2_bit(bit $b) {
One: { b->value= exp2((float)b->scale); }
Zero: { b->value= 0.0; }
}
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