System information

010B AF XRA A ;0 TO ACCUM
010C 326B01 STA HSTWRT ;NO PENDING WRITE
;
MATCH:
;COPY DATA TO OR FROM BUFFER
010F 3A6401 LDA SEKSEC ;MASK BUFFER NUMBER
0112 E603 ANI SECMSK ;LEAST SIGNIF BITS
0114 6F MOV L,A ;READY TO SHIFT
0115 2600 MVI H,0 ;DOUBLE COUNT
REPT 7 ;SHIFT LEFT 7
DAD H
ENDM
0117+29 DAD H
0118+29 DAD H
0119+29 DAD H
011A+29 DAD H
011B+29 DAD H
011C+29 DAD H
011D+29 DAD H
; HL HAS RELATIVE HOST BUFFER ADDRESS
011E 117701 LXI D,HSTBUF
0121 19 DAD D ;HL = HOST ADDRESS
0122 EB XCHG ;NOW IN DE
0123 2A7501 LHLD DMAADR ;GET/PUT CP/M DATA
0126 0E80 MVI C,128 ;LENGTH OF MOVE
0128 3A7301 LDA READOP ;WHICH WAY?
012B B7 ORA A
012C C23501 JNZ RWMOVE ;SKIP IF READ
;
; WRITE OPERATION, MARK AND SWITCH DIRECTION
012F 3E01 MVI A,1
0131 326B01 STA HSTWRT ;HSTWRT = 1
0134 EB XCHG ;SOURCE/DEST SWAP
;
RWMOVE:
;C INITIALLY 128, DE IS SOURCE, HL IS DEST
0135 1A LDAX D ;SOURCE CHARACTER
0136 13 INX D
0137 77 MOV M,A ;TO DEST
0138 23 INX H
0139 0D DCR C ;LOOP 128 TIMES
013A C23501 JNZ RWMOVE
;
; DATA HAS BEEN MOVED TO/FROM HOST BUFFER
013D 3A7401 LDA WRTYPE ;WRITE TYPE
Appendix G : Blocking and Deblocking Algorithms CP/M Operating System Manual
G-7