FRDSECT FRDSECT describes the fields used by to reference the four free chain element header blocks. FRDSECT is invoked by the macro The D!SFRT DSECT is pointed to ty a v-constant in and also by the lD!SFRT field in NUCCH. r 0 FREELN 8 10 FREELU 18 20 FREEHN
28 30 FREEHU 38 40 lFREET1B FRBELOW1 48 lC1LL 1*1 1*2 Hexadecimal Field
Displacement Hame Field Description, Conte_nts, Beaning o 10 20 30 lhe !.Qll.Q!!1!g FREELH DC FREELU DC FREEHN DC FREEHU DC Are the Four Free Chain Element Header -3F'0';IL1(FLiu+FLPA:iuciEY:HUCCODE,0) 3F'0',AL1(0,USERKEY,USERCOIE,O) 3F'0',AL1(FLNU.PLHC,NUCKEY,HUCCODE,O) 3F'O',AL1(FLHC,USERKEY,USERCODE,O) Blocks -Lov-storage nucleus
Low storage user chain
High storage nucleus
High storage user chain !.Q!l.Q!!1!g of .Q£ the
Four Free Chain Element Header Elocks pOliTEi--EQu---O------- ------Polnter to first free element NU! EQU 4 Number of elements in chain !AX EQU 8 !aximum size of an element FLAGSEQU 12 Flag byte FLCLH EQU FLCLB EQU FLHC EQU FLHU EQU FLPA EQU SKEY EQU in FLAGS --X'SO' X'qO' X'20' X'10' X'08' 13 in SKEY USERKEY EQU --x'io' NUCKEY EQU X'FO' Cleanup flag
Overlaid chain flag
High storage flag
Nucleus flag
Page availatle on chain Storage key for this chain User storage key
Nucleus storage key
186 IBM VM/370 Data Areas and Control Block Logic

FRnSECT Hexadecimal Field
Displacement Nalle Field Description, Contents, !eaning 40 44
48 4C 4D TCODE EQO USERCODE EQU NOCCODE EQO TRNCODE EQO OSIRCODE EQO SYSCODE EQO IUXCODE EQO *ONOSED EQO BLOCKLEN EQO AFREETAB DC FREELOW1 DS lCILL DS Ilag§ !!I FREEFLG1 DC FRF1C EQO FRF1V EQO FRF1N EQO FRF1E EQO FRF1L EQO FRF1H EQO FRF1M EQO FRF1B EQO IQllQ!!.ng FREEFLG2 DC !!.!!§ FRF2CL lU"In FRF2SVP EQO FRF2NOI EQO FRF2CKE EQO FRF2CKT EQO FRF2CKX EQO 14
in TCODE --1-----
2
3
4
5
5
15
16
A (0) F 1 201 BL1'0' 1*1 in FREEFLG1
-- X 'SCj",---- X'40' X'20' X'10' X'08' X'04' X'02' X'01' !!I!g !!Q1Q§ BL1'0' A*2 !.n 1'80' X'40' X'20' X'10' X'08' X'04' FREETAB table code
User free storage page
Nucleus free storage page
Transient area page Oser area page System page Maximum possible code value
Symbolic length of block
Address of PREETAB table Original value of FREELOWE (set by INIT2)
Address of caller (for errors) Conditional request Variable request
Nucleus request
FREE (vs FRFT) request
Low storage is OK High storage is OK Messages wanted on error TYPCALL equals BALR in macro !g ]2MSIRE Cleanup flag Variable pages request flag (SCHVPGE) Second initialization routine has not yet been
called by DMSINS Do a check each time FREE or FRET is called
Do a check this time Executing CHECK routine now
Free Chain Element POINTER--EQU---O-- Pointer to next FREE element
SIZE EQO 4 Size of this element in bytes Section 2. CMS rata Areas and Control Blocks 187