Hi João,
The following (and it may have probs, as it was not tested), simply turns on
the nth bit within an array. It could be changed to turn off the bit or perform
some other bit boolean operation. You shouldn't need to iterate through array
bytes or bits, as that would certainly slow things down. I tried to follow
Charles' suggestions, but it is very rough and needs checks for out of bounds
conditions, array size considerations, etc..
HTH,
Mike
*
XR R2,R2
XR R3,R3
XR R4,R4
*
LAY R2,12 <=== Input bit to turn on (rel to 0)
SRDL R2,3 /8 to get bytes to bypass
SRL R3,29 shift remainder into pos 61-63
IC R4,BitPos(R3) Prime R4 w/OI immediate value
LA R5,BitArray(R2) A(target byte) in BitArray
EX R4,OrBit Sets selected bit on
*
OrBit OI 0(R5),x'00' Set selected bit on in BitArray
*
BitArray DC XL256'00'
MaxBits EQU L'BitArray*8 Max bits in array (rel to 0)
*
BitPos EQU * Ident bit in target byte
Bit_0 DC BL1'10000000'
Bit_1 DC BL1'01000000'
Bit_2 DC BL1'00100000'
Bit_3 DC BL1'00010000'
Bit_4 DC BL1'00001000'
Bit_5 DC BL1'00000100'
Bit_6 DC BL1'00000010'
Bit_7 DC BL1'00000001'
*
-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On
Behalf Of João Reginato
Sent: Thursday, May 20, 2021 2:49 PM
To: [email protected]
Subject: RES: Macro to set a bit string
Importance: Low
Caution! This message was sent from outside your organization.
Thanks to everyone for the relevant notes.
Thank you Philippe for your macro.
Mine follows (just for comparison and understanding) but I've preferred yours:
MACRO
&NAME TBIT &ACT,&VAR,&BIT
&NAME LR R14,&BIT
SR R15,R15
SRDL R14,3
LA R14,&VAR.(R14)
SRL R15,29
AIF ('&ACT' EQ 'OFF').OFF
IC R15,=X'8040201008040201'(R15)
AIF ('&ACT' EQ 'TEST').TEST
OI 0(R14),*-*
EX R15,*-4
MEXIT
.TEST TM 0(R14),*-*
EX R15,*-4
MEXIT
.OFF IC R15,=X'7FBFDFEFF7FBFDFE'(R15)
B N&SYSNDX
NI 0(R14),*-*
N&SYSNDX EX R15,*-4
MEND
Regards
João
-----Mensagem original-----
De: IBM Mainframe Assembler List <[email protected]> Em nome de
Philippe Leite Enviada em: quinta-feira, 20 de maio de 2021 15:18
Para: [email protected]
Assunto: Re: Macro to set a bit string
A little fix related to LLILF position:
MACRO
TBIT &ACTION,&ARRAY,&BIT
LCLC &TBTIX
&TBTIX SETC 'TBT'.'&SYSNDX'
LR 14,&BIT
SRDL 14,3
SRL 15,29
LAY 1,&ARRAY
LA 1,0(14,1)
AIF ('&ACTION' EQ 'ON').ACON
AIF ('&ACTION' EQ 'OFF').ACOFF
AGO .ERROR1
.ACON ANOP
&TBTIX.O DS 0H
LLILF 14,X'00000080'
LTR 15,15
JZ &TBTIX.R
&TBTIX.L DS 0H
SRL 14,1
BCT 15,&TBTIX.L
&TBTIX.R DS 0H
EX 14,&TBTIX.X
B &TBTIX.F
&TBTIX.X OI 0(1),0
AGO .MEXIT
.ACOFF ANOP
&TBTIX.N DS 0H
LLILF 14,X'FFFFFF7F'
LTR 15,15
JZ &TBTIX.S
&TBTIX.M DS 0H
SRL 14,1
BCT 15,&TBTIX.M
&TBTIX.S DS 0H
EX 14,&TBTIX.Y
B &TBTIX.F
&TBTIX.Y NI 0(1),0
AGO .MEXIT
.ERROR1 ANOP
MNOTE 8,'*** ACTION PARAMETER INVALID'
AGO .MEXIT
.MEXIT ANOP
&TBTIX.F EQU *
MEND
Philippe Leite
z/OS System Programmer
