(→Variables) |
(→Postfix Code) |
||
Line 46: | Line 46: | ||
}} | }} | ||
− | + | {{CollapsedCode|Declaration of external function| | |
<asm> | <asm> | ||
EXTERN malloc | EXTERN malloc | ||
</asm> | </asm> | ||
+ | }} | ||
− | + | {{CollapsedCode|Function "mkvec"| | |
− | |||
<asm> | <asm> | ||
;; start of BB1 | ;; start of BB1 | ||
Line 99: | Line 99: | ||
;; end of BB4 | ;; end of BB4 | ||
</asm> | </asm> | ||
+ | }} | ||
− | + | {{CollapsedCode|Function "compute"| | |
− | |||
<asm> | <asm> | ||
;; start of BB1 | ;; start of BB1 | ||
Line 208: | Line 208: | ||
</asm> | </asm> | ||
+ | }} | ||
== Compiling and Running == | == Compiling and Running == |
Consider the following C code and assume that the size of pointers, int, and unsigned long is 32 bits and that the size of double is 64 bits.
<c> static unsigned long a = 10; static double *v; extern void *malloc(unsigned long);
static double *mkvec(unsigned long n) {
if (n < 1) return (double *)0; unsigned long s = sizeof(double); double *v = (double *)malloc(n * s); return v;
}
double *compute() {
v = mkvec(a * 4); for (unsigned long i = 1; i < a; i++) if (v[i] > v[0]) v[i] = 3 * i - 1; return v;
} </c>
The Postfix code for the above code is as follows: (code has not been thoroughly checked: bug reports are welcome)
In the following code sections, BB# means "basic block number".
Variables |
---|
<asm>
DATA ALIGN LABEL a CONST 10
DATA ; "static" variables are always initialized ALIGN LABEL v CONST 0 ; this is a null pointer </asm> |
Declaration of external function |
---|
<asm> EXTERN malloc </asm> |
Function "mkvec" |
---|
<asm>
TEXT ALIGN LABEL mkvec ENTER 8 ; s@-4 v@-8 LOCAL 8 LOAD INT 1 LT JZ ifend1
INT 0 POP LEAVE RET
ALIGN LABEL ifend1 INT 8 ; sizeof(double) LOCAL -4 STORE LOCAL +8 LOAD LOCAL -4 LOAD MUL CALL malloc
TRASH 4 PUSH LOCAL -8 STORE LOCAL -8 LOAD POP LEAVE RET
</asm> |
Function "compute" |
---|
<asm>
TEXT ALIGN GLOBAL compute, FUNC LABEL compute ENTER 4 ; i@-4 ADDR a LOAD INT 4 MUL CALL mkvec
TRASH 4 PUSH DUP ADDR v STORE TRASH 4 INT 1 LOCAL -4 STORE
ALIGN LABEL fortest LOCAL -4 LOAD ADDR a LOAD LT JZ forend
ADDR v LOAD LOCAL -4 LOAD INT 8 MUL ADD DLOAD ADDR v LOAD INT 0 INT 8 MUL ADD DLOAD DCMP INT 0 GT JZ ifend2
INT 3 LOCAL -4 LOAD MUL INT 1 SUB I2D DDUP ADDR v LOAD LOCAL -4 LOAD INT 8 MUL ADD DSTORE TRASH 8
ALIGN LABEL ifend2 ALIGN LABEL forincr LOCAL -4 LOAD DUP INT 1 ADD LOCAL -4 STORE TRASH 4 JMP fortest
ALIGN LABEL forend ADDR v LOAD POP LEAVE RET
</asm> |
To compile the Postfix code directly, pf2asm can be used (assuming a 32-bit architecture):
pf2asm compute.pf yasm -felf compute.asm