VFCB mapping

Table 1. Structure VFCB
`Offset`	`Offset`
`Dec`	`Hex`	`Type`	`Len`	`Name(Dim)`	`Description`
`0`	`(0)`	`STRUCTURE`	`44`	`VFCB`	`Virtual Fetch Control Block`
`0`	`(0)`	`CHARACTER`	`4`	`VFCBID`	`Control block ID ("VFCB")`
`4`	`(4)`	`ADDRESS`	`4`	`VFCBASCB`	`Address of Virtual Fetch address space ASCB`
`8`	`(8)`	`CHARACTER`	`8`	`VFCBRESH`	`Refresh number of this Virtual Fetch in TIMER units`
`8`	`(8)`	`SIGNED`	`4`	`VFCBRSH1`	`First half of refresh value`
`12`	`(C)`	`SIGNED`	`4`	`VFCBRSH2`	`Second half of refresh value`
`16`	`(10)`	`ADDRESS`	`4`	`VFCBHSHP`	`Address of hash table`
`20`	`(14)`	`UNSIGNED`	`4`	`VFCBHSHV`	`Hash algorithm divisor`
`24`	`(18)`	`SIGNED`	`4`	`VFCBECB`	`Refresh ECB`
`28`	`(1C)`	`UNSIGNED`	`1`	`VFCBLVEL`	`Level number of this VFCB (currently level=0)`
`29`	`(1D)`	`UNSIGNED`	`1`	`VFCBFLAG`	`Flag byte`
		`1... ....`		`VFCBUILT`	`Virtual Fetch has been built and is fully operational. (turned on after the VFCB is set up, and just before entering WAIT processing. It is initially off, and will be turned off before updating the VFCB, and whenever the ESTAE is entered).`
		`.1.. ....`		`VFCBRES2`	`Reserved flag`
		`..1. ....`		`VFCBRES3`	`Reserved flag`
		`...1 ....`		`VFCBRES4`	`Reserved flag`
		`.... 1...`		`VFCBRES5`	`Reserved flag`
		`.... .1..`		`VFCBRES6`	`Reserved flag`
		`.... ..1.`		`VFCBRES7`	`Reserved flag`
		`.... ...1`		`VFCBRES8`	`Reserved flag`
`30`	`(1E)`	`CHARACTER`	`2`	`VFCBRES9`	`Reserved half word`
`32`	`(20)`	`SIGNED`	`4`	`VFCBCSWD`	`Word for compare and swap. Used to serialize CSVVFTCH with the REFRESH function of CSVVFCRE.`
`32`	`(20)`	`UNSIGNED`	`1`	`VFCBRSCH`	`Refresh in progress flag field`
		`1... ....`		`VFCBRINP`	`Refresh in progress flag`
		`.111 1111`		`VFCBRV09`	`Reserved`
`33`	`(21)`	`BITSTRING`	`1`	`VFCBRV10`	`Reserved`
`34`	`(22)`	`SIGNED`	`2`	`VFCBGETS`	`Number of GET requests active.`
`36`	`(24)`	`SIGNED`	`4`	`VFCBGECB`	`ECB to be posted by GET process when refresh is in progress and GET count has just been decremented to zero`
`40`	`(28)`	`UNSIGNED`	`4`	`VFCBRSEQ`	`Refresh sequence number. It is incremented when refresh process begins and VFCBGETS=0. It is used to prevent an incorrect POST from GET process.`

Table 2. Constants for VFCB
`Len`	`Type`	`Value`	`Name`	`Description`
`4`	`DECIMAL`	`44`	`VFCBLEN`	`Length of the VFCB`

Table 3. Cross Reference for VFCB
`Name`	`Offset`	`Hex Tag`
`VFCB`	`0`
`VFCBASCB`	`4`
`VFCBCSWD`	`20`
`VFCBECB`	`18`
`VFCBFLAG`	`1D`
`VFCBGECB`	`24`
`VFCBGETS`	`22`
`VFCBHSHP`	`10`
`VFCBHSHV`	`14`
`VFCBID`	`0`
`VFCBLVEL`	`1C`
`VFCBRESH`	`8`
`VFCBRES2`	`1D`	`40`
`VFCBRES3`	`1D`	`20`
`VFCBRES4`	`1D`	`10`
`VFCBRES5`	`1D`	`08`
`VFCBRES6`	`1D`	`04`
`VFCBRES7`	`1D`	`02`
`VFCBRES8`	`1D`	`01`
`VFCBRES9`	`1E`
`VFCBRINP`	`20`	`80`
`VFCBRSCH`	`20`
`VFCBRSEQ`	`28`
`VFCBRSH1`	`8`
`VFCBRSH2`	`C`
`VFCBRV09`	`20`	`7F`
`VFCBRV10`	`21`
`VFCBUILT`	`1D`	`80`