AREGS

Abbreviation	None.
Arguments	None.
Default	AREGS
Description	The AREGS control causes the compiler to use absolute register addressing for registers R0 through R7. Absolute addressing improves the efficiency of the generated code. For example, PUSH and POP instructions function only with direct or absolute addresses. Using the AREGS directive, functions can directly push and pop registers. You may use the REGISTERBANK directive to define which register bank to use.

NOTE
Though it may defined several times in a program, the AREGS option is valid only when defined outside of a function declaration.

See Also

NOAREGS

Example

The following is a source and code listing using both NOAREGS and AREGS.

.
.
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stmt level    source
   1          extern char func ();
   2          char k;
   3
   4          #pragma NOAREGS
   5          noaregfunc ()  {
   6   1        k = func () + func ();
   7   1      }
   8
   9          #pragma AREGS
  10          aregfunc ()  {
  11   1        k = func () + func ();
  12   1      }
.
.
.
	; FUNCTION noaregfunc (BEGIN)
				; SOURCE LINE # 6
0000 120000	E	LCALL	func
0003 EF		MOV	A,R7
0004 C0E0		PUSH	ACC
0006 120000	E	LCALL	func
0009 D0E0		POP	ACC
000B 2F		ADD	A,R7
000C F500	R	MOV	k,A
				; SOURCE LINE # 7
000E 22		RET
	; FUNCTION noaregfunc (END)

	; FUNCTION aregfunc (BEGIN)
				; SOURCE LINE # 11
0000 120000	E	LCALL	func
0003 C007		PUSH	AR7
0005 120000	E	LCALL	func
0008 D0E0		POP	ACC
000A 2F		ADD	A,R7
000B F500	R	MOV	k,A
				; SOURCE LINE # 12
000D 22		RET
	; FUNCTION aregfunc (END)
.
.
.

Note the different methods of saving R7 on the stack. The code generated for the function noaregfunc is:

MOV  A,R7
PUSH ACC

while the code for the aregfunc function is:

PUSH AR7