;***************************************************************************;
; ;
; BASE ;
; AlphaBASIC subroutine - returns the base of a memory module ;
; ;
;***************************************************************************;
;Donated to AMUS on 19-Apr-86 by UltraSoft. All Rights Reserved.
;
;Written by: David Pallmann
;
;Edit History:
;1.0 19-Apr-86 created. /DFP
;
;Calling Format:
;
; XCALL BASE, module$, base
;
;Where: module$ - is a string variable or constant containing the
; name of the module to locate. The string must
; be in the format "{name}.{extension}".
;
; base - is a floating point variable, which receives the
; base address of the module. If the module is not
; in memory, a zero is returned. If the module
; specification is invalid, a zero is returned as
; well.
;
;Example:
;
; XCALL "MTSTAT.SYS", X
VMAJOR=1
VMINOR=0
OBJNAM .SBR
SEARCH SYS
SEARCH SYSSYM
;XCALL argument list set up by BASIC and indexed by A3
ENTRY: PHDR -1,PV$RSM,PH$REE!PH$REU ; program header
;check for correct number of arguments and for proper argument data types
CHECK: CMMW COUNT(A3),#2 ; 2 arguments specified?
JNE ARGERR ; no - error
CMMW TYPE1(A3),#STRING ; 1st argument string?
JNE TYPERR ; no - error
CMMW TYPE2(A3),#FLOAT ; 2nd argument string?
JNE TYPERR ; no - error
;translate the ASCII module name to RAD50 using the free memory set up
;basic and indexed by register A4.
XLATE: MOV ADDR1(A3),A2 ; point A2 to module name
ALF ; is module name valid?
BEQ 10$ ; yes
NUM ; is module name valid?
JNE NOTFND ; no
10$: FILNAM @A4,DAT ; convert ASCII @A2 to RAD50 @A4
;look for the module in system and user memory
LOOK: SRCH @A4,A0 ; look for module, A0 gets addres
JEQ RETURN ; found - branch
;clear out return code - module not found
NOTFND: SUB A0,A0 ; not found - clear A0
;convert module address A0 to floating point return codej
RETURN: MOV A0,D0
MOV ADDR2(A3),A1
FLTOF D0,@A1
;return to BASIC program
RTN
;error handling
ARGERR: TYPESP ?Incorrect number of arguments
BR ERROR
