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Digital-Research-Source-Code/CONTRIBUTIONS/z80em86/bios/dphunit.lib
Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

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;**************************************************************************
;* CP/M 3 BIOS for Z80em86 Z80 CPU emulator *
;* *
;* DPH unit byte definition for CP/M 3 *
;* *
;* Copyright (C) 1992-2009 Stewart Kay *
;**************************************************************************
;
; ChangeLog (most recent entries are at top)
; ------------------------------------------
; v1.0.0 - 16 February 2009, S.J.Kay
; - Prepare for public release.
;
; v1.00 - 17 April 1995, S.J.Kay
; - Undocumented changes.
;
; v0.00 - 1992, S.J.Kay
; - Initial creation date.
; DPH UNIT (@RDRV) byte mode bits
; bit 7, 6 - cylinder format
uddsk equ 00000000b ;double sided up-down disk
dsdsk equ 01000000b ;double sided disk
ssdsk equ 10000000b ;single sided disk
; bit 5, 4 - disk density
sden equ 00000000b ;single density
dden equ 00010000b ;double density
hden equ 00100000b ;high density
; bit 3, 2 - drive type
flp equ 00000000b ;floppy type
hdd equ 00000100b ;HDD drive type
ram equ 00001000b ;RAM drive type
; bit 1, 0 - drive select
drv0 equ 00000000b ;drive select code 0
drv1 equ 00000001b ;drive select code 1
drv2 equ 00000010b ;drive select code 2
drv3 equ 00000011b ;drive select code 3
; end of file