Difference between revisions of "Code Generation/Example 2"

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< Code Generation
(The Original Code)
(Postfix Code)
Line 20: Line 20:
 
ALIGN
 
ALIGN
 
LABEL _L123  ;; automatic label
 
LABEL _L123  ;; automatic label
STR "batata"
+
SSTRING "batata"
 
;--- declaring the global variable "a"
 
;--- declaring the global variable "a"
 
DATA
 
DATA
Line 30: Line 30:
 
TEXT
 
TEXT
 
ALIGN
 
ALIGN
GLOBL _main, FUNC
+
GLOBAL _main, FUNC
 
LABEL _main
 
LABEL _main
 
ENTER 0
 
ENTER 0
Line 36: Line 36:
 
ADDR a
 
ADDR a
 
LDINT
 
LDINT
EXTRN prints
+
EXTERN prints
 
CALL prints
 
CALL prints
 
TRASH 4
 
TRASH 4

Revision as of 13:29, 29 April 2020

The Original Code

Consider the following C function:

const char *a = "batata";
int main() {
  prints(a);
  return 0;
}

Postfix Code

The Postfix code for the above function is as follows:

Postfix code
;--- declaring the string literal
RODATA
ALIGN
LABEL _L123  ;; automatic label
SSTRING "batata"
;--- declaring the global variable "a"
DATA
ALIGN
LABEL a
SADDR  _L123  ;; automatic label

;--- this is the main function (note that "s9" translates to RTS's "_main")
TEXT
ALIGN
GLOBAL _main, FUNC
LABEL _main
ENTER 0

ADDR a
LDINT
EXTERN prints
CALL prints
TRASH 4

INT 0
STFVAL32
LEAVE
RET

Compiling and Running

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

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