Difference between revisions of "Code Generation/Example 4"

Revision as of 00:33, 2 May 2018

Consider the following C function:

<c> extern int printf(const char *format, ...); int printlist(int lo, int hi) {

 int ix = lo;
 while (ix < hi) {
   printf("%d\n", ix);
   ix++;
 }
 return ix;

} </c>

The Postfix code for the above function is as follows:

Postfix code
{{{2}}}

To compile the Postfix code directly, pf2asm can be used:

@@ Line 31: / Line 31: @@
 ; int ix = lo is NOT an assignment
 LOCAL +8
-LOAD ; read lo
+LDINT ; read lo
 LOCAL -4
-STORE ; write to ix
+STINT ; write to ix
 ALIGN
 LABEL whiletest
 LOCAL -4
-LOAD  ; read ix
+LDINT  ; read ix
 LOCAL +12
-LOAD ; read hi
+LDINT ; read hi
 LT
 JZ whileend
@@ Line 49: / Line 49: @@
 LOCAL -4
-LOAD     ; second printf arg: read ix
+LDINT     ; second printf arg: read ix
 ; put string literal in read-only memory
@@ Line 55: / Line 55: @@
 ALIGN
 LABEL strlit
-STR "%d\n"
+SSTRING "%d\n"
 ; now get the address of the string literal (strlit)
 TEXT
@@ Line 67: / Line 67: @@
 ; get printf return value
-PUSH
+LDFVAL32
 ; get rid of return value (printf used as instruction)
@@ Line 74: / Line 74: @@
 ; increment ix
 LOCAL -4
-LOAD ; read ix
+LDINT ; read ix
-DUP
+DUP32
 INT 1
 ADD
 LOCAL -4
-STORE ; ix = ix + 1
+STINT ; ix = ix + 1
 ; trash old value of ix
@@ Line 95: / Line 95: @@
 ; prepare return value
 LOCAL -4
-LOAD ; read ix
+LDINT ; read ix
 ; put it in the accumulator (register) to conform with Cdecl
-POP
+STFVAL32
 LEAVE  ; release stack frame