Code Generation/Example 2

The Original Code

Consider the following S9 function:

<c> string a = "batata"; int s9() -> 0 {

     a!

} </c>

Postfix Code

The Postfix code for the above function is as follows:

<asm>

--- declaring the string literal

RODATA ALIGN LABEL _L123  ;; automatic label STR "batata"

--- declaring the global variable "a"

DATA ALIGN LABEL a ID _L123  ;; automatic label

--- this is the main function (note that "s9" translates to RTS's "_main")

TEXT ALIGN GLOBL _main, FUNC LABEL _main ENTER 0

ADDRV a  ;; ADDRV = ADDR+LOAD EXTRN prints CALL prints TRASH 4

INT 0 POP LEAVE RET </asm>

Compiling and Running

To test the first example, the S9 compilation process is as follows:

• s9 batata.s9
• yasm -felf batata.asm
• ld -o batata batata.o -lrts

To test the second program directly, pf2asm can be used:

• pf2asm batata.pf
• yasm -felf batata.asm
• ld -o batata batata.o -lrts