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Elite on the BBC Micro

Save and load: CATD (Disc version)

Name: CATD [View in context] Type: Subroutine Category: Save and load Summary: Load disc sectors 0 and 1 to &0E00 and &0F00 respectively
This routine is copied to &0D7A in part 1 above. It is called by both the main docked code and the main flight code, just before the docked code, flight code or shup blueprint files are loaded.
.CATD DEC CATBLOCK+8 \ Decrement sector number from 1 to 0 DEC CATBLOCK+2 \ Decrement load address from &0F00 to &0E00 JSR CATL \ Call CATL to load disc sector 1 to &0E00 INC CATBLOCK+8 \ Increment sector number back to 1 INC CATBLOCK+2 \ Increment load address back to &0F00 .CATL LDA #127 \ Call OSWORD with A = 127 and (Y X) = CATBLOCK to LDX #LO(CATBLOCK) \ load disc sector 1 to &0F00 LDY #HI(CATBLOCK) JMP OSWORD .CATBLOCK EQUB 0 \ 0 = Drive = 0 EQUD &00000F00 \ 1 = Data address = &0F00 EQUB 3 \ 5 = Number of parameters = 3 EQUB &53 \ 6 = Command = &53 (read data) EQUB 0 \ 7 = Track = 0 EQUB 1 \ 8 = Sector = 1 EQUB %00100001 \ 9 = Load 1 sector of 256 bytes EQUB 0 \ 10 = The result of the OSWORD call is returned here COPYBLOCK CATD, P%, CATDcode ORG CATDcode + P% - CATD