home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
ftp.barnyard.co.uk
/
2015.02.ftp.barnyard.co.uk.tar
/
ftp.barnyard.co.uk
/
cpm
/
walnut-creek-CDROM
/
ENTERPRS
/
CPM
/
UTILS
/
S
/
ZCNFG21.LZH
/
CFGLIB.LZH
/
PKGOFF.Z80
< prev
next >
Wrap
Text File
|
1992-11-03
|
896b
|
25 lines
ext z3env
public pkgoff
; Calculate address of a package from Z3ENV. On entry, E
; contains the offset to the address of the package in the environment. On
; exit, DE points to the beginning of the package and HL points to the fifth
; byte (where the command table starts in the RCP and FCP modules). The zero
; flag is set on return if the package is not supported.
pkgoff:
ld hl,(z3env) ; Point to beginning of ENV descriptor
ld a,l
or h ;test for no z3env
ret z
ld d,0 ; Make DE have offset
add hl,de ; ..and add it
ld e,(hl) ; Get low byte of package address
inc hl ; Point to high byte
ld d,(hl) ; ..and get it
ld a,d ; Move full address into HL
or e ; Set zero flag if no package
ret ; Return with zero flag set appropriately
end