Register parameters
RST 20H, DEFW $87
IN: A = reason code HL, IX arguments Reason codes are as follows: DR_GET ($01) get handle for a DOR name (internal use) DR_DUP ($02) duplicate DOR DR_SIB ($03) return brother DOR DR_SON ($04) return child DOR DR_FRE ($05) free DOR handle DR_CRE ($06) create blank DOR DR_DEL ($07) delete DOR DR_INS ($08) insert DOR DR_RD ($09) read DOR record DR_WR ($0A) write DOR record OUT, if call successful: Fc = 0 returned values depend on A(in) OUT, if call failed: Fc = 1 A = error code: RC_HAND ($08), bad handle RC_BAD ($04), bad argument RC_ROOM ($07), no room RC_EOF ($09), end of file Registers changed after return: not documented.
Notes
When the last DOR record in a list has been read, an RC_EOF is reported and the handle is immediatly released, ie. it will not be necessary to release the handle with a DR_FRE call.
Bugs
Corrupts the stack pointer SP when called with an old handle, e.g. when a previous DR_ call resulted in a "End of list" error (RC_EOF).
Reason code specifications
DR_GET ($01), get a handle for a DOR name (internal usage)
IN: HL = pointer to a string (full path with device name) OUT, if call successful: Fc = 0 IX = DOR handle A = minor type Registers changed after return: ..BCDEHL/..IY same AF....../IX.. different Do not use this call. Instead use GN_Opf with A = OP_DOR to obtain a DOR handle.
DR_DUP ($02), duplicate DOR
IN: IX = DOR handle OUT, if call successful: Fc = 0 BC = duplicate DOR handle (IX is still valid) OUT, if call failed: Fc = 1 BC = 0 (IX is still valid) A = error code RC_HAND ($08), bad DOR handle Registers changed after return: ....DEHL/IXIY same AFBC..../.... different
DR_SIB ($03), return brother DOR
IN: IX = DOR handle OUT, if call successful: Fc = 0 IX = next DOR handle (original IX invalid) A = minor type OUT, if call failed: Fc = 1 A = error code RC_HAND ($08), bad DOR handle Registers changed after return: ..BCDEHL/..IY same AF....../IX.. different
DR_SON ($04), return child DOR
IN: IX = DOR handle OUT, if call successful: Fc = 0 IX = child DOR handle (original IX invalid) A = minor type OUT, if call failed: Fc = 1 A = error code RC_HAND ($08), bad DOR handle Registers changed after return: ..BCDEHL/..IY same AF....../IX.. different
DR_FRE ($05), free DOR handle
IN: IX = DOR handle OUT, if call successful: Fc = 0 IX = 0 OUT, if call failed: Fc = 1 A = error code RC_HAND ($08), bad DOR handle Registers changed after return: ..BCDEHL/..IY same AF....../IX.. different
DR_CRE ($06), create blank DOR
IN: IX = parent DOR handle B = minor type OUT, if call successful: Fc = 0 IX = new DOR handle (original IX invalid) OUT, if call failed: Fc = 1 A = error code RC_HAND ($08), bad DOR handle RC_BAD ($04), bad argument RC_ROOM ($07), no room Registers changed after return: ..BCDEHL/..IY same AF....../IX.. different
DR_DEL ($07), delete DOR
IN: IX = DOR handle OUT, if call successful: Fc = 0, DOR deleted IX = 0 OUT, if call failed: Fc = 1 A = error code RC_HAND ($08), bad DOR handle Registers changed after return: ..BCDEHL/..IY same AF....../IX.. different
DR_INS ($08), insert DOR
IN: BC = parent DOR handle IX = DOR handle OUT, if call successful: Fc = 0 original BC and IX DOR handles are still valid OUT, if call failed: Fc = 1 BC and IX is still valid A = error code RC_HAND ($08), bad DOR handle Registers changed after return: ..BCDEHL/IXIY same AF....../.... different
DR_RD ($09), read DOR record
IN: B = record type C = buffer length DE = user buffer address (to store information of read) IX = DOR handle OUT, if call successful: Fc = 0 original IX DOR handle is still valid C = actual length of information OUT, if call failed: Fc = 1 original IX is still valid A = error code RC_HAND ($08), bad DOR handle RC_BAD ($04), bad argument RC_FAIL ($16), information is not present Registers changed after return: ..B.DEHL/IXIY same AF.C..../.... different
DR_WR ($0A), write DOR record
IN: B = record type C = buffer length DE = user buffer address (to copy information of store) IX = DOR handle OUT, if call successful: Fc = 0 original IX DOR handle is still valid OUT, if call failed: Fc = 1 original IX is still valid A = error code RC_HAND ($08), bad DOR handle RC_BAD ($04), bad argument Registers changed after return: ..BCDEHL/IXIY same AF....../.... different