The following pure-Postfix program illustrates duplication of double-precision floating point numbers on the stack.
The C equivalent would be (roughly):
<c> int main() {
extern void printd(double); double d, e; d = e = 3.3e-2; printd(d + e); return 0;
} </c>
Note that this program's code does not necessarily correspond to any particular code generator output.
Postfix code |
---|
<asm>
TEXT ALIGN GLOBAL _main, FUNC LABEL _main ENTER 16 ; d@-8 and e@-16
RODATA ALIGN LABEL _L123 DOUBLE 3.3e-2
TEXT ADDR _L123 DLOAD
DDUP LOCAL -16 ; write value to "e" DSTORE
DDUP LOCAL -8 ; write value to "d" DSTORE
TRASH 8
LOCAL -8 DLOAD ; load "d" LOCAL -16 DLOAD ; load "e" DADD ; leaves result on the stack EXTERN printd CALL printd TRASH 8 ; argument value no longer needed INT 0 POP LEAVE RET </asm> |
Assuming that the code above is in file dbl.pf, the following commands would compile and run the program:
pf2asm dbl.pf yasm -felf dbl.asm ld -o dbl dbl.o -lrts ./dbl