Code Generation/Example 4 - Revision history

Root: Redirected page to ist:Code Generation/Example 4

2018-12-06T18:14:31Z

Redirected page to ist:Code Generation/Example 4

← Older revision		Revision as of 18:14, 6 December 2018
Line 1:		Line 1:
	~~== The Original~~ Code ==		#REDIRECT [[ist:Code Generation/Example 4]]

	~~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>

	~~== Postfix Code ==~~

	~~The Postfix code for the above function is as follows:~~
	~~{{CollapsedCode\|Postfix code\|~~
	~~<asm>~~
	~~EXTRN printf~~

	~~TEXT~~
	~~ALIGN~~
	~~GLOBL printlist, FUNC~~
	~~LABEL printlist~~

	~~ENTER 4 ; ix@-4 lo@+8 hi@+12~~

	~~; int ix = lo is NOT an assignment~~
	~~LOCAL +8~~
	~~LDINT ; read lo~~
	~~LOCAL -4~~
	~~STINT ; write to ix~~

	~~ALIGN~~
	~~LABEL whiletest~~
	~~LOCAL -4~~
	~~LDINT ; read ix~~
	~~LOCAL +12~~
	~~LDINT ; read hi~~
	LT
	~~JZ whileend~~

	~~; start while body~~

	~~; prepare arguments for calling printf~~

	~~LOCAL -4~~
	~~LDINT ; second printf arg: read ix~~

	~~; put string literal in read-only memory~~
	~~RODATA~~
	~~ALIGN~~
	~~LABEL strlit~~
	~~SSTRING "%d\n"~~
	~~; now get the address of the string literal (strlit)~~
	~~TEXT~~
	~~ADDR strlit ; first printf arg: string literal address~~

	~~; args are in the stack: call the function~~
	~~CALL printf~~

	~~; clean args~~
	~~TRASH 8~~

	~~; get printf return value~~
	~~LDFVAL32~~

	~~; get rid of return value (printf used as instruction)~~
	~~TRASH 4~~

	~~; increment ix~~
	~~LOCAL -4~~
	~~LDINT ; read ix~~
	~~DUP32~~
	~~INT 1~~
	~~ADD~~
	~~LOCAL -4~~
	~~STINT ; ix = ix + 1~~

	~~; trash old value of ix~~
	~~TRASH~~ 4

	~~; end while body~~

	~~; restart while cycle~~
	~~JMP whiletest~~

	~~; this is the while exit point~~
	~~ALIGN~~
	~~LABEL whileend~~

	~~; prepare return value~~
	~~LOCAL -4~~
	~~LDINT ; read ix~~

	~~; put it in the accumulator (register) to conform with Cdecl~~
	~~STFVAL32~~

	~~LEAVE ; release stack frame~~
	~~RET ; return control to caller~~

	~~</asm>~~
	}}

	~~== Compiling and Running ==~~

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

	* pf2asm while.pf
	* yasm -felf while.asm

	~~[[category:Compiladores]]~~
	~~[[category:Ensino~~]]

Root: /* Postfix Code */

2018-05-01T22:33:03Z

Postfix Code

← Older revision		Revision as of 22:33, 1 May 2018
Line 31:		Line 31:
	; int ix = lo is NOT an assignment		; int ix = lo is NOT an assignment
	LOCAL +8		LOCAL +8
	~~LOAD~~ ; read lo		LDINT ; read lo
	LOCAL -4		LOCAL -4
	~~STORE~~ ; write to ix		STINT ; write to ix

	ALIGN		ALIGN
	LABEL whiletest		LABEL whiletest
	LOCAL -4		LOCAL -4
	~~LOAD~~ ; read ix		LDINT ; read ix
	LOCAL +12		LOCAL +12
	~~LOAD~~ ; read hi		LDINT ; read hi
	LT		LT
	JZ whileend		JZ whileend
Line 49:		Line 49:

	LOCAL -4		LOCAL -4
	~~LOAD~~ ; second printf arg: read ix		LDINT ; second printf arg: read ix

	; put string literal in read-only memory		; put string literal in read-only memory
Line 55:		Line 55:
	ALIGN		ALIGN
	LABEL strlit		LABEL strlit
	~~STR~~ "%d\n"		SSTRING "%d\n"
	; now get the address of the string literal (strlit)		; now get the address of the string literal (strlit)
	TEXT		TEXT
Line 67:		Line 67:

	; get printf return value		; get printf return value
	~~PUSH~~		LDFVAL32

	; get rid of return value (printf used as instruction)		; get rid of return value (printf used as instruction)
Line 74:		Line 74:
	; increment ix		; increment ix
	LOCAL -4		LOCAL -4
	~~LOAD~~ ; read ix		LDINT ; read ix
	~~DUP~~		DUP32
	INT 1		INT 1
	ADD		ADD
	LOCAL -4		LOCAL -4
	~~STORE~~ ; ix = ix + 1		STINT ; ix = ix + 1

	; trash old value of ix		; trash old value of ix
Line 95:		Line 95:
	; prepare return value		; prepare return value
	LOCAL -4		LOCAL -4
	~~LOAD~~ ; read ix		LDINT ; read ix

	; put it in the accumulator (register) to conform with Cdecl		; put it in the accumulator (register) to conform with Cdecl
	~~POP~~		STFVAL32

	LEAVE ; release stack frame		LEAVE ; release stack frame

Root: /* Postfix Code */

2017-05-09T07:31:07Z

Postfix Code

← Older revision		Revision as of 07:31, 9 May 2017
Line 18:		Line 18:

	The Postfix code for the above function is as follows:		The Postfix code for the above function is as follows:
			{{CollapsedCode\|Postfix code\|
	<asm>		<asm>
	EXTRN printf		EXTRN printf
Line 30:		Line 30:

	; int ix = lo is NOT an assignment		; int ix = lo is NOT an assignment
	~~LOCV~~ +8 ; read lo		LOCAL +8
	~~LOCA~~ -4 ; write to ix		LOAD ; read lo
			LOCAL -4
			STORE ; write to ix

	ALIGN		ALIGN
	LABEL whiletest		LABEL whiletest
	~~LOCV~~ -4 ; read ix		LOCAL -4
	~~LOCV~~ +12 ; read hi		LOAD ; read ix
			LOCAL +12
			LOAD ; read hi
	LT		LT
	JZ whileend		JZ whileend
Line 44:		Line 48:
	; prepare arguments for calling printf		; prepare arguments for calling printf

	~~LOCV~~ -4 ; second printf arg: read ix		LOCAL -4
			LOAD ; second printf arg: read ix

	; put string literal in read-only memory		; put string literal in read-only memory
Line 68:		Line 73:

	; increment ix		; increment ix
	~~LOCV~~ -4 ; read ix		LOCAL -4
			LOAD ; read ix
	DUP		DUP
	INT 1		INT 1
	ADD		ADD
	~~LOCA~~ -4 ; ix = ix + 1		LOCAL -4
			STORE ; ix = ix + 1

	; trash old value of ix		; trash old value of ix
Line 87:		Line 94:

	; prepare return value		; prepare return value
	~~LOCV~~ -4 ; read ix		LOCAL -4
			LOAD ; read ix

	; put it in the accumulator (register) to conform with Cdecl		; put it in the accumulator (register) to conform with Cdecl
Line 96:		Line 104:

	</asm>		</asm>
			}}

	== Compiling and Running ==		== Compiling and Running ==

Root: /* Postfix Code */

2016-06-16T16:49:27Z

Postfix Code

← Older revision		Revision as of 16:49, 16 June 2016
Line 73:		Line 73:
	ADD		ADD
	LOCA -4 ; ix = ix + 1		LOCA -4 ; ix = ix + 1

			; trash old value of ix
			TRASH 4

	; end while body		; end while body

Root: /* Postfix Code */

2015-05-11T09:27:22Z

Postfix Code

← Older revision		Revision as of 09:27, 11 May 2015
Line 41:		Line 41:

	; start while body		; start while body

			; prepare arguments for calling printf

	LOCV -4 ; second printf arg: read ix		LOCV -4 ; second printf arg: read ix

Line 86:		Line 89:
	POP		POP

	; release stack frame		LEAVE ; release stack frame
	~~LEAVE~~		RET ; return control to caller

	; return control to caller
	~~RET~~

	</asm>		</asm>

Root: /* Postfix Code */

2015-05-11T09:25:25Z

Postfix Code

← Older revision		Revision as of 09:25, 11 May 2015
Line 39:		Line 39:
	LT		LT
	JZ whileend		JZ whileend

			; start while body
			LOCV -4 ; second printf arg: read ix

	; put string literal in read-only memory		; put string literal in read-only memory
Line 45:		Line 48:
	LABEL strlit		LABEL strlit
	STR "%d\n"		STR "%d\n"
			; now get the address of the string literal (strlit)
			TEXT
			ADDR strlit ; first printf arg: string literal address

	~~TEXT~~		; args are in the stack: call the function
	; ~~start while body~~
	~~LOCV -4 ; second printf arg: read ix~~
	~~ADDR strlit ; first printf arg~~: ~~string lit address~~
	CALL printf		CALL printf

Root at 14:30, 6 April 2015

2015-04-06T14:30:16Z

← Older revision		Revision as of 14:30, 6 April 2015
Line 98:		Line 98:
	* yasm -felf while.asm		* yasm -felf while.asm

	[[category:~~Compilers~~]]		[[category:Compiladores]]
	[[category:~~Teaching~~]]		[[category:Ensino]]

Root: /* Postfix Code */

2013-05-07T10:23:24Z

Postfix Code

← Older revision		Revision as of 10:23, 7 May 2013
Line 37:		Line 37:
	LOCV -4 ; read ix		LOCV -4 ; read ix
	LOCV +12 ; read hi		LOCV +12 ; read hi
			LT
	JZ whileend		JZ whileend

Root: Created page with "== The Original Code == Consider the following C function: extern int printf(const char *format, ...); int printlist(int lo, int hi) { int ix = lo; while (ix < hi) { ..."

2011-05-13T21:05:33Z

Created page with "== The Original Code == Consider the following C function: <c> extern int printf(const char *format, ...); int printlist(int lo, int hi) { int ix = lo; while (ix < hi) { ..."

New page

== The Original Code ==

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>

== Postfix Code ==

The Postfix code for the above function is as follows:

<asm>
EXTRN printf

TEXT
ALIGN
GLOBL printlist, FUNC
LABEL printlist

ENTER 4 ; ix@-4 lo@+8 hi@+12

; int ix = lo is NOT an assignment
LOCV +8 ; read lo
LOCA -4 ; write to ix

ALIGN
LABEL whiletest
LOCV -4 ; read ix
LOCV +12 ; read hi
JZ whileend

; put string literal in read-only memory
RODATA
ALIGN
LABEL strlit
STR "%d\n"

TEXT
; start while body
LOCV -4 ; second printf arg: read ix
ADDR strlit ; first printf arg: string lit address
CALL printf

; clean args
TRASH 8

; get printf return value
PUSH

; get rid of return value (printf used as instruction)
TRASH 4

; increment ix
LOCV -4 ; read ix
DUP
INT 1
ADD
LOCA -4 ; ix = ix + 1

; end while body

; restart while cycle
JMP whiletest

; this is the while exit point
ALIGN
LABEL whileend

; prepare return value
LOCV -4 ; read ix

; put it in the accumulator (register) to conform with Cdecl
POP

; release stack frame
LEAVE

; return control to caller
RET

</asm>

== Compiling and Running ==

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

* pf2asm while.pf
* yasm -felf while.asm

[[category:Compilers]]
[[category:Teaching]]