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Unused, but reserved data in the overlay data_group

Hello,

i'm using die uvision2, cx51 7.2 for a philips mx chip. In my following example code, keil reserves data, which is assigned to registers und so furthermore not used.
The problem only comes, when i'm using more params as can all be passed through registers.

thanks for help, solving the problem.

the .c file:

#include <REG51M.H>

typedef unsigned char byteT;
typedef unsigned int  shortT;

void test(shortT param1, shortT param2, shortT param3,shortT param4);
shortT sub2(shortT param1, shortT param2 );

void main(void)
{
	test(0x0011, 0x0022, 0x0033, 0x0044);
	while(1){}
}

void test(shortT param1, shortT param2, shortT param3,shortT param4)
{
	shortT param5 =sub2(param1, param2)+ param3;
	param4++;
}

shortT sub2(shortT param1, shortT param2)
{
	return param1+param2;
}

the map

FUNCTION/MODULE              BIT_GROUP   DATA_GROUP
--> CALLED FUNCTION/MODULE  START  STOP  START  STOP
====================================================
?C_C51STARTUP               ----- -----  ----- -----
  +--> ?PR?MAIN?MAIN

MAIN/MAIN                   ----- -----  ----- -----
  +--> ?PR?_TEST?MAIN

_TEST/MAIN                  ----- -----  0008H 0011H
  +--> ?PR?_SUB2?MAIN

_SUB2/MAIN                  ----- -----  ----- -----

and the .src

	RSEG  ?DT?_test?MAIN
?_test?BYTE:
     param1?140:   DS   2
     param2?141:   DS   2
     param3?142:   DS   2
     param4?143:   DS   2
	ORG  8
     param5?144:   DS   2
; #include <REG51M.H>
;
; typedef unsigned char byteT;
; typedef unsigned int  shortT;
;
; void test(shortT param1, shortT param2, shortT param3,shortT param4);
; shortT sub2(shortT param1, shortT param2 );
;
; void main(void)

	RSEG  ?PR?main?MAIN
main:
	USING	0
			; SOURCE LINE # 9
; {
			; SOURCE LINE # 10
; 	test(0x0011, 0x0022, 0x0033, 0x0044);
			; SOURCE LINE # 11
	MOV  	?_test?BYTE+06H,#00H
	MOV  	?_test?BYTE+07H,#044H
	MOV  	R3,#033H
	MOV  	R2,#00H
	MOV  	R5,#022H
	MOV  	R4,#00H
	MOV  	R7,#011H
	MOV  	R6,#00H
	LCALL	_test
?C0001:
; 	while(1){}
			; SOURCE LINE # 12
	SJMP 	?C0001
; END OF main

; }
;
; void test(shortT param1, shortT param2, shortT param3,shortT param4)

	RSEG  ?PR?_test?MAIN
_test:
	USING	0
			; SOURCE LINE # 15
	MOV  	param3?142,R2
	MOV  	param3?142+01H,R3
;---- Variable 'param2?141' assigned to Register 'R4/R5' ----
;---- Variable 'param1?140' assigned to Register 'R6/R7' ----
; {
			; SOURCE LINE # 16
; 	shortT param5 =sub2(param1, param2)+ param3;
			; SOURCE LINE # 17
	LCALL	_sub2
	MOV  	A,param3?142+01H
	ADD  	A,R7
	MOV  	param5?144+01H,A
	MOV  	A,param3?142
	ADDC 	A,R6
	MOV  	param5?144,A
; 	param4++;
			; SOURCE LINE # 18
	INC  	param4?143+01H
	MOV  	A,param4?143+01H
	JNZ  	?C0006
	INC  	param4?143
?C0006:
; }
			; SOURCE LINE # 19
	RET
; END OF _test

;
; shortT sub2(shortT param1, shortT param2)

	RSEG  ?PR?_sub2?MAIN
_sub2:
	USING	0
			; SOURCE LINE # 21
;---- Variable 'param2?246' assigned to Register 'R4/R5' ----
;---- Variable 'param1?245' assigned to Register 'R6/R7' ----
; {
			; SOURCE LINE # 22
; 	return param1+param2;
			; SOURCE LINE # 23
	MOV  	A,R7
	ADD  	A,R5
	MOV  	R7,A
	MOV  	A,R6
	ADDC 	A,R4
	MOV  	R6,A
; }
			; SOURCE LINE # 24
?C0005:
	RET
; END OF _sub2