fujinet Can I use this as a possible XIO 39/40 routine in my N: handler?

[tschak909]

Could I use the below code (this is from the DOS 2.0 source code), as a starting point for my XIO 39/40 implementation?

 

1170         .PAGE
1171 ;=========================================================================
1172 ;  ****  LOADER ROUTINE  *** 
1173 ;=========================================================================
1174 ;       LOADS FROM THE FILE (MUST BE LOAD FORMAT)
1175 ;       INTO MEMORY. RETURNS:
1176 ;         X=0 LOAD OK
1177 ;         X=1 OPEN ERRORS Y=CIO CODE
1178 ;         X=2 READ ERRORS Y=CIO CODE
1179 ;         X=3 BAD LOAD FILE
1180 ; ON ENTRY, IOCB 1 POINTS TO FILENAME.
1181 ;-------------------------------------------------------------------------
1182 DUPFLG  .BYTE   0               ;FLAG -IF DUP IN MEMORY NOT ZERO
1183 OPT     .BYTE   0               ;HOLDS VALUE OF OPTION GIVEN BY USER
1184 LOADFG  .BYTE   0               ;FLAG = $80 IF MEMORY FILE DOESN'T HAVE
1185 HDBUF   *=*+4
1186         HILO    HDBUF
1187 HDBUFH     =       HDBUF/256
1188 HDBUFL     =       (-256)*HDBUFH+HDBUF
1189 SFLOAD  LDA     #$80
1190 STLOAD  STA     LOADFG
1191 LOAD    LDA     #.LOW.RTS
1192         STA     RUNAD
1193         LDA     #.HIGH.RTS
1194         STA     RUNAD+1         ;MAKE RUN AT EOF DEFAULT TO RTS
1195         LDX     #$10
1196         LDA     #OPEN
1197         STA     ICCOM,X
1198         LDA     #4              ;OPEN TYPE=INPUT
1199         STA     ICAX1,X
1200         JSR     CIO             ;TRY TO OPEN FILE
1201         BPL     RDLF            ;CONT IF OK
1202         LDA     #1              ;OPEN ERRORS
1203         BNE     CLFX            ;CLOSE AND EXIT
1204 RDLF    LDX     #$10
1205         LDA     #.LOW.DBUFL
1206         STA     ICBAL,X
1207         LDA     #.LOW.DBUFH
1208         STA     ICBAH,X
1209         LDA     #2
1210         STA     ICBLL,X
1211         LDA     #0
1212         STA     ICBLH,X
1213         STA     MEMLDD          ;CLEAR MEM.SAV LOADED FLAG
1214         LDA     #GETCHR
1215         STA     ICCOM,X
1216         JSR     CIO
1217         BMI     ERST            ;IF ERRS
1218         LDA     #$FF
1219         CMP     DBUF            ;CHECK FOR VALID LOAD FILE
1220         BNE     LNLF
1221         CMP     DBUF+1
1222         BNE     LNLF            ;BRANCH IF NOT A LOAD FILE
1223 RDDRC   LDX     #$10
1224         LDA     #.LOW.HDBUFL
1225         STA     ICBAL,X
1226         LDA     #.LOW.HDBUFH
1227         STA     ICBAH,X
1228         LDA     #4
1229 RDDRC1  STA     ICBLL,X
1230         LDA     #0
1231         STA     ICBLH,X
1232         JSR     CIO             ;NO ERROR CHECK SO CAN CATCH EOF
1233         BPL     STOK            ;IF NO ERROR
1234         CPY     #$88            ;SEE IF EOF
1235         BNE     ERST            ;IF SOME ERROR STATUS
1236 ;=========================================================================
1237 ;EOF SO DONE, EXIT
1238 ;=========================================================================
1239         JSR     CLOSX           ;CLOSE IOCB'S 1 AND 2
1240         BIT     OPT
1241         BMI     DRUN            ;BRANCH IF NO RUN OPTION
1242         JSR     JMPRUN          ;JUMP THROUGH RUN VECTOR
1243 DRUN    LDA     #0              ;OK STATUS
1244         BIT     LOADFG          ;WAS MEMORY SWAPPED?
1245         STA     LOADFG
1246         BMI     CLFX            ;BRANCH IF MEMORY WASN'T SWAPPED
1247         JSR     MEMSVQ          ;DOES MEMORY SAVE FILE EXIST?
1248         BMI     DRUN1           ;BRANCH IF NOT
1249         PLA
1250         PLA
1251         JMP     GOOD            ;WRITE MEMORY AND RELOAD DUP
1252 ;=========================================================================
1253 ;       SEE IF DUP WRITTEN OVER. IF IS RELOAD & TELL USER NEED MEM.SAV TO
1254 ;       LOAD THIS FILE.
1255 ;=========================================================================
1256 DRUN1   LDA     DUPFLG          ;SEE IF DUP CLOBBERED
1257         BNE     DRUN2           ;NO, THEN RETURN
1258         LDA     #.LOW.NMSFL     ;ELSE TELL USER NEED MEM.SAV
1259         LDX     #.LOW.NMSFH
1260         JSR     PRNTMSG         ;PRINT MSG
1261         JMP     RRDUP           ;RELOAD & RUN DUP
1262 ;=========================================================================
1263 ;       RETURN TO CALLING ROUTINE
1264 ;=========================================================================
1265 DRUN2   LDA     #0              ;NO DUP ERR MSG ON EOF
1266 CLFX    TAX
1267 RTS     RTS

-Thom

[Alfred]

As a starting point, sure. You can likely lose anything that relates to DUP.

[Rybags]

It doesn't seem to do much - only grabs the first 2 bytes, validatest $FFFF as a loadable file then grabs the following 4 bytes for start/length.

 

The binary load algorithm is fairly simple and you can easily just do your own.

[Alfred]

I assumed he just didn’t post the rest of the routine since what’s listed is incomplete.

[tschak909]

Yeah, sorry, the rest of it is there, I just didn't grab it all. still trying to work through what to do.

 

Believe it or not, my assembler-fu is terrible.

 

-Thom