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Raj Shetgar Posted
17-Dec-2003 05:55 GMT Toolset
C51 |  using "USING 0"directive Raj Shetgar Hello All,
I am trying to use the assembler directive "using" but I don't see the expected results, the code is as follows
;--------------------------------------
name one
extrn code (loop2,loop3)
prog segment code
cseg at 0
using 0
jmp start
rseg prog
start: mov sp,#30h
loop:
mov r1,#1
mov r2,#2
lcall loop2
lcall loop3
jmp loop
end
;--------------------------------------
name two
public loop2
prg1 segment code
rseg prg1
using 1
loop2:
mov r3,#3
mov r4,#4
ret
end
;--------------------------------------
name three
public loop3
prg2 segment code
rseg prg2
using 2
loop3:
mov r5,#5
mov r6,#6
ret
end
;--------------------------------------
what I wanted to do in the above code is see the contents in different register banks.
and also to my surprise I saw only 7 bits in the psw register while debugging where is the other PSW4(register select bit)...?
Question
--------
Suppose I have a subroutine, which should use a different register bank and at the end of return it should reinitialize to the previous register bank...is there any other directive to do that or should I use push psw and pop pws ?
Rgds
Raj Shetgar | | Read-Only Author
Support Keil Posted
17-Dec-2003 08:44 GMT Toolset
C51 | RE: using "USING 0"directive Support Keil The USING attribute does not switch register bank. It adjusts only the symbols AR0 - AR7 that are required for absolute registerbank addressing.
Take a look to the Assembler/Utilities User's Guide for more information.
Also the file C51\ASM\Template.A51 shows you how to switch registerbanks and how to apply the USING attribute. | | Read-Only Author
Graham Cole Posted
17-Dec-2003 09:15 GMT Toolset
C51 | RE: using "USING 0"directive Graham Cole While in debug, the psw can be expanded to show seven fields. Each of these fields is just one bit except the rs field which is two bits and can take values 0 to 3. | |
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