CBXBLOK,CBYBLOK CBXBLOK and CBYBLOK provide the necessary control for a virtual machine using a virtual
channel-to-channel adapter (CTCA). The VDEVBEAL field in the VDEVBLCK points to CBIELOK and CBYBLOK fer virtual CTCAs. 0 CBXOTBB CBYOTBR 8 X*l X*2 , X*3 I X*4 Y*l I Y*2 Y*3 Y*4 10 CBXNCCW CBYNCCli 18 CBIBCNT CHYRCNT 20 CBXSTAT CBXYADD CBYSTAT CBYXIDD 28 CBXIDAW CBYIDAli 30 CBXCNCT CHYCNCT 38 CHXDATN CHYDATN lote: As indicated in the illustrated block, the CBIBLOK and CHYELCK are interleaved
with a 4-byte displacement. The X-side VDEVELOK points to the +0 slot, the Y-side VDEVBLOK points to the +4 slot; however, once the virtual connection is made, either side
can be the X-side or the Y-side since this interleaved arrangement makes the contrel block references completely symmetrical. The dual DSICT definition allows the active
adapter (defined to be the I-side, arbitrarily) to reference beth adapter sides
concurrently wi-thout knowing whether i tis at +0 or +4. Bexadecimal Field tisplacement Name o
8
9 A CBXBLOK CBXOTBB DS CBXFLAG DS CBBl!NOP EQU CBBM370 EQU CHBATTN EQU CBBREST EQU CBBEOFL EQU CBBBIO EQU CBBWAIT EQU CBBCENT EQU CBXCMDB DS CBXCMDT DS CBBCTNL EQU CBBRDBK EQU CBBWEOF EQU CBBSCMD EQU CBBSADS EQU CBBREAD EQU CBBWRIT EQU 2F lX in CBIFLIG -X'80'- X'40' X'20' X'10' X'08' X'04' X'02' X'Ol' lX lX in CBICMDT -X'40'- X'20' X'10' X'08' X'04' X'02' X'Ol' Field Description, Contents, Meaning I-side channel adapter block Vl!ELCK address of Y-side adapter user X*l Internal processing flags
Modified NOF command issued (also in CMDT) CTCA operating in Systea/370 mede Attention pending from Y-side CTCA has been reset I-side and Y-side Force EOF to next READ instruction
Halt I/O or halt device issued CPEXELOK available--for channel reconnect Channel end has preserved en SIO X*2 Active CCW command byte buffer X*3 Active CCli command type (Rt, WB, etc.) Control, other than NOP Read backward Write EOF Sense command byte Sense adapter status
Bead
write
12 IBM VM/370 Data Areas and Control Block Logic

Hexadecimal
Displacement
------------
B C 10 18 20 22
24
28 30 38
o
8
9
A
B C 10 18 20 22
24
28 30 38
Field
Name CHXPKEY DS DS CHXNCCW DS CHIRCNT DS CBXSTAT DS CHXYADD DS DS CBXIDAW DS CBXCNCT DS CBXDATN DS CBBSIZE EQU 1X 4X 2F
2F
1B
1B
2B
2F
2F
2F CBXBLOK,CBYELCK . Field Description, Contents, eeaning X*4 Virtual CAW protection key
"Other" adapter control flags
Next CCW fetch address (real)
Remaining CCW data count tevice status accumulation field Virtual address of Y-side adaFter
"Other" adaFter control flags
Active indirect data list word CPEXELOK for channel reconnect IOELCK address for deferred I/O interruFt (*-CBXBLOK)/8 Total block size in doublewords (X'08') CBYBLOK Y-side channel adapter block CBYOTBR DS CBYFLAG DS CBBMNOP EQU CBBM370 EQU CBBATTN EQU CBBREST EQU CBBEOFL EQU CBBBIO EQU CBBWAIT EQU CBBEENT EQU CHYCMDB DS CBYCMDT DS Bit§ CBBCNTL EQU CBBRDBK EQU CBBWEOF EQU CBBSCMD EQU CHBS!DS EQU CBBREAD EQU CBBWRIT EQU CHYPKEY DS DS CHYNCCW DS CBYRCNT DS CBYSTAT DS CHYXADD DS DS CBYIDAW DS CBYCNCT DS CBYDATN DS 2F 1X in CBYFLAG --X'SO'- X'40' X'20' X'10' X'08' X'04' X'02' X'01' 1X 1X in CBYCMDT -x''4o'­ X'20' X'10' X'08' X'04' X'02' X'01' 1X 4X 2F
2F
1B
1B
2B
2F
2F
2F VMELCK address of X-side adaFter user Y*1 Internal processing flags Modified NOF command issued (also in CMDT) CTCA operating in System/370 mode
Attention pending from X-side CTCA has been reset X-side and Y-side Force EOF to next READ instruction
Halt 1/0 or halt device issued CPEXELOK availatle for channel reconnect Channel end has been preserved cn SIO Y*2 Active CCW command tyte buffer Y*3 Active CCW command type (Rt, WB, etc.) Control, other than NOP Read tackward Write EOF Sense command byte
Sense adapter status
Bead
write Y*4 Virtual CAW protection key
"Other" adapter control flags
Next CCW fetch address (real)
Bemaining CCW data count
Device status accumulation field Virtual address of X-side adaFter
"Other" adaFter control flags
Active indirect data list word CPEXELOK for channel reconnect IOELCK address for deferred I/O interruFt
Section 1. CP Data Areas and Centrol Blocks 13