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Source Code
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Written by Jeremiah Stoddard
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Sunday, 20 April 2008 16:38 |
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The ProDOS Machine Language Interface allows the assembly language programmer to utilize ProDOS disk functions. An MLI call consists of JSR $BF00 followed by three bytes. The first byte is a number identifying the function you want to use (e.g. $C7 identifies the function GET_PREFIX which returns the current prefix), and the next two bytes contain the address of a parameter list. The first byte of the parameter list is the number of parameters, followed by the parameters themselves. This is documented in the ProDOS 8 Technical Reference Manual, but in case it's of help to anyone, I've provided (below) an example of using a ProDOS MLI call from the ORCA/M Macro Assembler. ORCA also has Macros to take care of MLI calls, but that can be discussed at another time.
* GP - GET PREFIX
* AN EXAMPLE OF USING THE PRODOS $C6 MLI CALL TO GET THE DEFAULT PREFIX.
* THE DEFAULT PREFIX (IF ANY) IS PRINTED TO THE SCREEN.
KEEP GP
MAIN START
JSR $BF00 PRODOS MLI ROUTINE
DC H´C7´ FILL NEXT BYTE WITH $C7 - GET PREFIX
DC A´ARGS´ ADDRESS TO ADDRESS OF BUFFER
CMP #$00
BNE END THERE WAS AN ERROR
LDA PNAME NUMBER OF CHARACTERS
CMP #$00
BEQ END
TAY
LDX #$01
LOOP LDA PNAME,X
ORA #$80 COUT EXPECTS MSB TO BE ON
JSR $FDED COUT
INX
DEY
BNE LOOP
END RTS
ARGS DC H´01´ NUMBER OF PARAMETERS
DC A´PNAME´ LOCATION OF THE PATHNAME
PNAME DS 64 THE PATHNAME WILL GO HERE
END |
