Code Generation/Example 2: Difference between revisions
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| Line 1: | Line 1: | ||
== The Original Code == | == The Original Code == | ||
Consider the following | Consider the following C function: | ||
<source lang="c"> | <source lang="c"> | ||
const char *a = "batata"; | |||
int | int main { | ||
prints(a); | |||
return 0; | |||
} | } | ||
</source> | </source> | ||
Revision as of 07:04, 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
STR "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
GLOBL _main, FUNC
LABEL _main
ENTER 0
ADDR a
LDINT
EXTRN prints
CALL prints
TRASH 4
INT 0
STFVAL32
LEAVE
RET
|
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