Appendix B

The Inkey Program

Assembly Language Listing of Inkey

 An assembled version of Inkey is included on the CONFIG/ BASIC09 diskette. Use Inkey from BASIC09 with the RUN statement.

 ~ INKEY - a subroutine for BASIC09 by Robert Doggett

 ~ Called by; RUN INKEY(StrVar)
 RUN INKEY(Path,StrVar) ~ INKEY determines if a key has been typed on the given path ~ (Standard Input if not specified), and if so, returns the next ~ character in the String Variable. If no key has been typed, the ~ null string is returned, If a path i5 Specified, it must be ~ either type BYTE or INTEGER.




0021 TYPE
 0081 REVS
0000 87CDOOSE

OOOD 496E6H65 D 0000 D 0000 D 0002 D 0004 D 0006 D 0008 D 000A

000C
 000E
 0012 3064
Set SHRTN+OBJCT
 Set REENT+1


Return rmb
 PCount rmb
 Param1 rmb
 Length1 rmb
 Param2 rmb
 Length2 rmb
 E3Param e9u
 SIZE equ
 InKeyEnt leax

 mod InKeyEnd,InKeyNam,TYPE,REVS
 ,InKeyEnt,SIZE

 "Inkey"

 0
 2
 2
 2
 2
 2
 2
 $38

 Paraml,S

 Parameters Return addr of caller Num of params following 1st param addr Size 2nd param addr size
 BASIC09 Commands Reference
0014 EC62 ldd Pcount,S Get parameter count
 0016 10830001 cmpd x1 just one parameter?
 001A 2727 beq InKey20 _Yes; default path A=0
 001C 10830002 cmpd x2 Are there two param5?
 0020 2635 bne ParamErr No, abort
 0022 ECF804 ldd fParam1,S] Get path number
 0025 AE66 ldx Lengthl,S
 0027 301E leax -1,X byte variable?
 0029 2706 beq InKey10 _Yes; (A)=Path number
 002E 301E leax -1,X Integer?
 002D 2628 bne ParamErr _ No; abort
 002E 1F98 tfr H,A
 0031 3068 InKey10 leax Param2,S
 0033 EE02 InKey20 ldu 2,X length of string
 0035 AE84 ldx O,X addr of string
 0037 C6FF ldb xsFF
 0039 E784 stb O,X Initialize to null str
 0038 11830002 cmpu #2 at least two-byte str?
 003E 2502 blo InKey30 _ No
 0041 E701 5tb 1,X put str terminator
 0043 C601 InKey30 ldb #SS,Ready
 0045 103FBD OS9 I$GetStt i5 there any data ready?
 0048 2508 bcs InKey90 _ No; exit
 004A 108E0001 ldy x1
 004E 103F89 OS9 I$Read Read one byte
 0051 39 rt5 returns error status
 0052 C1F6 InKey90 cmpb xE$NotRdy
 0054 2603 bne InKeyErr
 0056 39 its (carry clear)
 0057 C638 ParamErr ldb xESParam Parameter Error
 0059 43 InKeyErr coma
 005A 39 its
 0058 1A6916 emod
 005E InKeyEnd equ

 B-2