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⌂ ∞ ▽ Elite on the 6502

Save and load: CATBLOCK

[BBC Micro disc version, Loader 3]

       Name: CATBLOCK                                                [Show more]
       Type: Subroutine
   Category: Save and load
    Summary: OSWORD block for loading  disc sectors 0 and 1
  Deep dive: Swapping between the docked and flight code

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * CATD calls CATBLOCK
             * Elite loader (Part 1 of 3) calls CATBLOCK




.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