44428e53b6
- General cleanup of codebase - Fixed condition codes m6800.c from Roberto Sancho Villa - Add additional FDC lfd-400 from Roberto Sancho Villa - Add additional OS's (FLEX 1.0, FDOS 1.0, DOS68, MiniDOS, and MiniDOS-MPX) to software support - Add additional disk formats to software support dc-4.c from Roberto Sancho Villa - Add CPU history - Fix LOAD/DUMP to support binary and hex - Fix fprintf_sym to disassemble 6800 code correctly - Add EXAMINE/DEPOSIT to CPU Memory - Fixed disasm to space the register - Add SET_FLAG(IF) to IRQ – fixed error in handling IRQ from Roberto Sancho Villa
652 lines
26 KiB
C
652 lines
26 KiB
C
/* c: SWTP DC-4 FDC Simulator
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Copyright (c) 2005-2012, William A. Beech
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Permission is hereby granted, free of charge, to any person obtaining a
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copy of this software and associated documentation files (the "Software"),
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to deal in the Software without restriction, including without limitation
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the rights to use, copy, modify, merge, publish, distribute, sublicense,
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and/or sell copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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WILLIAM A BEECH BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Except as contained in this notice, the name of William A. Beech shall not
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be used in advertising or otherwise to promote the sale, use or other dealings
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in this Software without prior written authorization from William A. Beech.
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MODIFICATIONS:
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28 May 22 -- Roberto Sancho Villa (RSV) fixes for other disk formats
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and operating systems.
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NOTES:
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The DC-4 is a 5-inch floppy controller which can control up
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to 4 daisy-chained 5-inch floppy drives. The controller is based on
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the Western Digital 1797 Floppy Disk Controller (FDC) chip. This
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file only emulates the minimum DC-4 functionality to interface with
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the virtual disk file.
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The floppy controller is interfaced to the CPU by use of 5 memory
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addreses. These are SS-30 slot numbers 5 and 6 (0x8014-0x801B).
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Address Mode Function
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------- ---- --------
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0x8014 Read Returns FDC interrupt status
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0x8014 Write Selects the drive/head/motor control
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0x8018 Read Returns status of FDC
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0x8018 Write FDC command register
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0x8019 Read Returns FDC track register
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0x8019 Write Set FDC track register
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0x801A Read Returns FDC sector register
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0x801A Write Set FDC sector register
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0x801B Read Read data
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0x801B Write Write data
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Drive Select Read (0x8014):
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+---+---+---+---+---+---+---+---+
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| I | D | X | X | X | X | X | X |
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+---+---+---+---+---+---+---+---+
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I = Set indicates an interrupt request from the FDC pending.
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D = DRQ pending - same as bit 1 of FDC status register.
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Drive Select Write (0x8014):
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+---+---+---+---+---+---+---+---+
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| M | S | X | X | X | X | Device|
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+---+---+---+---+---+---+---+---+
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M = If this bit is 1, the one-shot is triggered/retriggered to
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start/keep the motors on.
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S = Side select. If set, side one is selected otherwise side zero
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is selected.
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X = not used
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Device = value 0 thru 3, selects drive 0-3 to be controlled.
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Drive Status Read (0x8018):
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+---+---+---+---+---+---+---+---+
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| R | P | H | S | C | L | D | B |
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+---+---+---+---+---+---+---+---+
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B - When 1, the controller is busy.
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D - When 1, index mark detected (type I) or data request - read data
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ready/write data empty (type II or III).
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H - When 1, track 0 (type I) or lost data (type II or III).
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C - When 1, crc error detected.
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S - When 1, seek (type I) or RNF (type II or III) error.
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H - When 1, head is currently loaded (type I) or record type/
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write fault (type II or III).
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P - When 1, indicates that diskette is write-protected.
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R - When 1, drive is not ready.
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Drive Control Write (0x8018) for type I commands:
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+---+---+---+---+---+---+---+---+
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| 0 | S2| S1| S0| H | V | R1| R0|
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+---+---+---+---+---+---+---+---+
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R0/R1 - Selects the step rate.
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V - When 1, verify on destination track.
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H - When 1, loads head to drive surface.
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S0/S1/S2 = 000 - home.
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001 - seek track in data register.
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010 - step without updating track register.
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011 - step and update track register.
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100 - step in without updating track register.
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101 - step in and update track register.
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110 - step out without updating track register.
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111 - step out and update track register.
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Drive Control Write (0x8018) for type II commands:
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+---+---+---+---+---+---+---+---+
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| 1 | 0 | T | M | S | E | B | A |
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+---+---+---+---+---+---+---+---+
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A - Zero for read, 1 on write deleted data mark else data mark.
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B - When 1, shifts sector length field definitions one place.
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E - When, delay operation 15 ms, 0 no delay.
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S - When 1, select side 1, 0 select side 0.
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M - When 1, multiple records, 0 for single record.
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T - When 1, write command, 0 for read.
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Drive Control Write (0x8018) for type III commands:
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+---+---+---+---+---+---+---+---+
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| 1 | 1 | T0| T1| 0 | E | 0 | 0 |
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+---+---+---+---+---+---+---+---+
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E - When, delay operation 15 ms, 0 no delay.
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T0/T1 - 00 - read address command.
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10 - read track command.
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11 - write track command.
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Tracks are numbered from 0 up to one minus the last track in the 1797!
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Track Register Read (0x8019):
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+---+---+---+---+---+---+---+---+
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| Track Number |
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+---+---+---+---+---+---+---+---+
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Reads the current 8-bit value from the track position.
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Track Register Write (0x8019):
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+---+---+---+---+---+---+---+---+
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| Track Number |
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+---+---+---+---+---+---+---+---+
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Writes the 8-bit value to the track register.
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Sectors are numbers from 1 up to the last sector in the 1797!
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Sector Register Read (0x801A):
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+---+---+---+---+---+---+---+---+
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| Sector Number |
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+---+---+---+---+---+---+---+---+
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Reads the current 8-bit value from the sector position.
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Sector Register Write (0x801A):
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+---+---+---+---+---+---+---+---+
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| Sector Number |
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+---+---+---+---+---+---+---+---+
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Writes the 8-bit value to the sector register.
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Data Register Read (0x801B):
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+---+---+---+---+---+---+---+---+
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| Data |
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+---+---+---+---+---+---+---+---+
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Reads the current 8-bit value from the data register.
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Data Register Write (0x801B):
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+---+---+---+---+---+---+---+---+
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| Data |
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+---+---+---+---+---+---+---+---+
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Writes the 8-bit value to the data register.
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A FLEX disk is defined as follows:
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(first sector on track is number 1)
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Track Sector Use
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0 1 Boot sector
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0 2 Boot sector (cont)
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0 3 Unused
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0 4 System Identity Record (explained below)
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0 5 Unused
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0 6-last Directory - 10 entries/sector (explained below)
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1 1 First available data sector
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last-1 last Last available data sector
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System Identity Record (SIR)
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Byte Use
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0x00 Two bytes of zeroes (Clears forward link)
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0x10 Volume name in ASCII(11 bytes)
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0x1B Volume number in binary (2 bytes)
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0x1D Address of first free data sector (Track-Sector) (2 bytes)
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0x1F Address of last free data sector (Track-Sector) (2 bytes)
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0x21 Total number of data sectors in binary (2 bytes)
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0x23 Current date (Month-Day-Year) in binary
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0x26 Highest track number on disk in binary (byte)
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0x27 Highest sector number on a track in binary (byte)
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The following unit registers are used by this controller emulation:
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dsk_unit[cur_drv].u3 unit current flags
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dsk_unit[cur_drv].u4 unit current track
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dsk_unit[cur_drv].u5 unit current sector
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dsk_unit[cur_drv].pos unit current sector byte index into buffer
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dsk_unit[cur_drv].filebuf unit current sector buffer
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dsk_unit[cur_drv].fileref unit current attached file reference
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*/
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#include <stdio.h>
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#include "swtp_defs.h"
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#define UNIT_V_ENABLE (UNIT_V_UF + 0) /* Write Enable */
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#define UNIT_ENABLE (1 << UNIT_V_ENABLE)
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/* emulate a SS FLEX disk with 72 sectors and 80 tracks */
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#define NUM_DISK 4 /* standard 1797 maximum */
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#define SECT_SIZE 256 /* standard FLEX sector */
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#define NUM_SECT 36 //sectors/track
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#define TRAK_SIZE (SECT_SIZE * NUM_SECT) /* trk size (bytes) */
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#define HEADS 2 //handle as DS
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#define NUM_CYL 80 /* maximum cylinders */
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#define DSK_SIZE (NUM_SECT * HEADS * NUM_CYL * SECT_SIZE) /* dsk size (bytes) */
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//SIR offsets TK 0, SEC 3
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#define LABEL 0x10 //disk label (11 char)
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#define VOLNUM 0x1B //volume number (word)
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#define FSTUSRTRK 0x1D //first user track (byte)
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#define FSTUSRSEC 0x1E //first user sector (byte)
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#define LSTUSRTRK 0x1F //last user track (byte)
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#define LSTUSRSEC 0x20 //last user sector (byte)
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#define TOTSEC 0x21 //total sectors (word)
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#define CREMON 0x23 //creation month (byte)
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#define CREDAY 0x24 //creation day (byte)
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#define CREYR 0x25 //creation year (byte)
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#define MAXCYL 0x26 //last cylinder #
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#define MAXSEC 0x27 //last sector #
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/* 1797 status bits type I commands*/
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#define NOTRDY 0x80
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#define WRPROT 0x40
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#define HEDLOD 0x20
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#define SEEKERR 0x10
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#define CRCERR 0x08
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#define LOST 0x04
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#define INDEX 0x02
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#define BUSY 0x01
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/* 1797 status bits type II/III commands*/
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#define NOTRDY 0x80
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#define WRPROT 0x40
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#define WRTFALT 0x20
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#define RECNF 0x10
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#define CRCERR 0x08
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#define LOST 0x04
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#define DRQ 0x02
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#define BUSY 0x01
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/* function prototypes */
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t_stat dsk_reset (DEVICE *dptr);
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t_stat dsk_attach (UNIT *uptr, CONST char *cptr);
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/* SS-50 I/O address space functions */
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int32 fdcdrv(int32 io, int32 data);
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int32 fdccmd(int32 io, int32 data);
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int32 fdctrk(int32 io, int32 data);
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int32 fdcsec(int32 io, int32 data);
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int32 fdcdata(int32 io, int32 data);
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/* Local Variables */
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int32 fdcbyte;
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int32 intrq; /* interrupt request flag */
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int32 cur_dsk; /* Currently selected drive */
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int32 wrt_flag; /* FDC write flag */
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int32 spt; /* sectors/track */
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int32 trksiz; /* trk size (bytes) */
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int32 heds; /* number of heads */
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int32 cpd; /* cylinders/disk */
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int32 dsksiz; /* dsk size (bytes) */
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int32 sectsize; // Sector size (bytes)
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int32 multiple_sector; // multiple read-write flag
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int32 index_countdown; // index countdown for type I commands
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int32 sector_base; // indicates is first sector on track is sector 1 or sector 0
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/* Floppy Disk Controller data structures
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dsk_dev Disk Controller device descriptor
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dsk_unit Disk Controller unit descriptor
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dsk_reg Disk Controller register list
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dsk_mod Disk Controller modifiers list
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*/
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UNIT dsk_unit[] = {
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{ UDATA (NULL, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+UNIT_ROABLE, 0) },
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{ UDATA (NULL, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+UNIT_ROABLE, 0) },
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{ UDATA (NULL, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+UNIT_ROABLE, 0) },
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{ UDATA (NULL, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+UNIT_ROABLE, 0) }
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};
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REG dsk_reg[] = {
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{ HRDATA (DISK, cur_dsk, 4) },
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{ NULL }
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};
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MTAB dsk_mod[] = {
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{ UNIT_ENABLE, UNIT_ENABLE, "RW", "RW", NULL },
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{ UNIT_ENABLE, 0, "RO", "RO", NULL },
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{ 0 }
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};
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DEBTAB dsk_debug[] = {
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{ "ALL", DEBUG_all, "All debug bits" },
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{ "FLOW", DEBUG_flow, "Flow control" },
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{ "READ", DEBUG_read, "Read Command" },
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{ "WRITE", DEBUG_write, "Write Command"},
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{ NULL }
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};
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DEVICE dsk_dev = {
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"DC-4", //name
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dsk_unit, //units
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dsk_reg, //registers
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dsk_mod, //modifiers
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NUM_DISK, //numunits
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16, //aradix
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16, //awidth
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1, //aincr
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16, //dradix
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8, //dwidth
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NULL, //examine
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NULL, //deposit
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&dsk_reset, //reset
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NULL, //boot
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dsk_attach, //attach
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NULL, //detach
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NULL, //ctxt
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DEV_DISABLE|DEV_DEBUG, //flags
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0, //dctrl
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dsk_debug, //debflags
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NULL, //msize
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NULL //lname
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};
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/* Reset routine */
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t_stat dsk_reset (DEVICE *dptr)
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{
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uint32 i;
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cur_dsk = 5; /* force initial SIR read */
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for (i=0; i<dptr->numunits; i++) {
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dptr->units[i].u3 = NOTRDY; /* current flags = NOTRDY*/
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dptr->units[i].u4 = 0; /* clear current cylinder # */
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dptr->units[i].u5 = 0; /* clear current sector # */
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dptr->units[i].pos = 0; /* clear current byte ptr */
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if (dptr->units[i].filebuf == NULL) {
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dptr->units[i].filebuf = calloc(SECT_SIZE, sizeof(uint8)); /* allocate buffer */
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if (dptr->units[i].filebuf == NULL) {
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printf("dc-4_reset: Calloc error\n");
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return SCPE_MEM;
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}
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}
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}
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spt = 0;
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trksiz = 0;
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heds = 0;
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cpd = 0;
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dsksiz = 0;
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//RSV - for hansling multiple disk formats and OSs
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sectsize = SECT_SIZE;
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multiple_sector=0;
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index_countdown=0;
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sector_base=1;
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return SCPE_OK;
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}
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/* dsk attach - attach an .IMG file to an FDD */
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t_stat dsk_attach (UNIT *uptr, CONST char *cptr)
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{
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t_stat r;
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if ((r = attach_unit (uptr, cptr)) != SCPE_OK) {
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sim_printf("dsk_attach: Attach error %d\n", r);
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return r;
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}
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uptr->u3 &= ~NOTRDY; //reset FDD to ready
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uptr->capac = sim_fsize(uptr->fileref); //file size
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return SCPE_OK;
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}
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/* I/O instruction handlers, called from the MP-B2 module when a
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read or write occur to addresses 0x8014-0x801B. */
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/* DC-4 drive select register routine - this register is not part of the 1797
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*/
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int32 fdcdrv(int32 io, int32 data)
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{
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static long pos;
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static int32 err;
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uint8 *SIR;
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int32 disk_image_size;
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if (io) { // write to DC-4 drive register
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if (cur_dsk == (data & 0x03)) // already selected?
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return 0; //yes
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cur_dsk = data & 0x03; // only 2 drive select bits/
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dsk_unit[cur_dsk].u3 &= ~LOST; //RSV - reset LOST flag
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if ((dsk_unit[cur_dsk].flags & UNIT_ENABLE) == 0) //RO?
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dsk_unit[cur_dsk].u3 |= WRPROT; /* Set WPROT */
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else
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dsk_unit[cur_dsk].u3 &= ~WRPROT; /* SET not WPROT */
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if (dsk_unit[cur_dsk].fileref == 0) // no file attached
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return 0;
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/* RSV - Read in SIR */
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pos = 0x200;
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sim_fseek(dsk_unit[cur_dsk].fileref, pos, SEEK_SET); /* seek to SIR */
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sim_fread(dsk_unit[cur_dsk].filebuf, SECT_SIZE, 1, dsk_unit[cur_dsk].fileref); /* read in SIR */
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dsk_unit[cur_dsk].u3 |= BUSY | DRQ; /* set DRQ & BUSY */
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dsk_unit[cur_dsk].pos = 0; /* clear counter */
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SIR = (uint8 * )(dsk_unit[cur_dsk].filebuf);
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// detect disk type based on image geometry or SIR record
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disk_image_size = sim_fsize(dsk_unit[cur_dsk].fileref); //get actual file size
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if (disk_image_size == 35 * 10 * 256) { // 89600 bytes -> FDOS image
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// FDOS disc has no SIR record.
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spt = 10; // 10 sectors
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cpd = 35; // 35 tracks
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sectsize = 256;
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sector_base = 0; // first sector in track is number ZERO
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} else if (disk_image_size == 35 * 18 * 128) { // 80640 bytes -> FLEX 1.0 image
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spt = 18; // 18 sectors
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cpd = 35; // 35 tracks
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sectsize = 128;
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sector_base = 1; // first sector in track is number ONE
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} else if ((SIR[0] == 0) && (SIR[1] == 0)) {
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// FLEX disc has SIR record. on disk image offset $200
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spt = SIR[MAXSEC]; // Highest number of tracks. As in FLEX sectors are numbered as
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// 1,2,..Hi this is also the number of sectors per track
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cpd = SIR[MAXCYL] + 1; // highest track number . On FLEX, first track is track zero
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sectsize = 256;
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sector_base = 1; // first sector in track is number ONE
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|
} else {
|
|
spt = 18;
|
|
sectsize = 128;
|
|
cpd = disk_image_size / (spt * sectsize);
|
|
sector_base = 1; // first sector in track is number ONE
|
|
}
|
|
heds = 0; //RSV - always SS
|
|
trksiz = spt * sectsize;
|
|
dsksiz = trksiz * cpd;
|
|
|
|
return 0;
|
|
} else { /* read from DC-4 drive register */
|
|
return intrq;
|
|
}
|
|
}
|
|
|
|
/* WD 1797 FDC command register routine */
|
|
|
|
int32 fdccmd(int32 io, int32 data)
|
|
{
|
|
static int32 val = 0, val1 = NOTRDY;
|
|
static long pos;
|
|
static int32 err;
|
|
|
|
if ((dsk_unit[cur_dsk].flags & UNIT_ATT) == 0) { /* not attached */
|
|
val = dsk_unit[cur_dsk].u3 |= NOTRDY; /* set not ready flag */
|
|
return SEEKERR; // RSV - return SEEK ERROR STATUS bit
|
|
} else {
|
|
dsk_unit[cur_dsk].u3 &= ~(NOTRDY); /* clear not ready flag */
|
|
}
|
|
if (io) { /* write command to fdc */
|
|
// RSV - on commands type I ...
|
|
if ((data & 0x80) == 0) {
|
|
// ... set bits h V r1r0 to h=1 (home drive), V=0 (verify off), r1r0=11 (40msec track stepping)
|
|
data = ((data & 0xF0) | 0x0B);
|
|
// and starts countdown for index status bit
|
|
index_countdown = 10;
|
|
} else {
|
|
index_countdown = 0;
|
|
}
|
|
// process command
|
|
switch(data) {
|
|
case 0x8C: //read sector command type II
|
|
case 0x9C: //read multiple sectors command type II
|
|
if ((dsk_unit[cur_dsk].u5 - sector_base >= spt) || (dsk_unit[cur_dsk].u5 < sector_base)) {
|
|
dsk_unit[cur_dsk].u3 |= RECNF; /* RSV - set RECORD NOT FOUND */
|
|
break;
|
|
}
|
|
dsk_unit[cur_dsk].u3 |= BUSY; /* set BUSY */
|
|
pos = trksiz * dsk_unit[cur_dsk].u4; /* calculate file offset */
|
|
pos += sectsize * (dsk_unit[cur_dsk].u5 - sector_base);
|
|
err = sim_fseek(dsk_unit[cur_dsk].fileref, pos, SEEK_SET); /* seek to offset */
|
|
if (err) {
|
|
sim_printf("fdccmd: Seek error in read command\n");
|
|
return SCPE_IOERR;
|
|
}
|
|
/* read in buffer */
|
|
err = sim_fread(dsk_unit[cur_dsk].filebuf, sectsize, 1, dsk_unit[cur_dsk].fileref);
|
|
if (err != 1) {
|
|
sim_printf("fdccmd: File error in read command\n");
|
|
return SCPE_IOERR;
|
|
}
|
|
dsk_unit[cur_dsk].u3 |= DRQ; /* set DRQ */
|
|
dsk_unit[cur_dsk].pos = 0; /* clear counter */
|
|
multiple_sector = (data == 0x9C) ? 1:0; // RSV = set multiple sector TYPE II cmds
|
|
break;
|
|
case 0xAC: //write command type II
|
|
case 0xBC: //write multiple sectors command type II
|
|
if (dsk_unit[cur_dsk].u3 & WRPROT) {
|
|
} else {
|
|
dsk_unit[cur_dsk].u3 |= BUSY;/* set BUSY */
|
|
pos = trksiz * dsk_unit[cur_dsk].u4; /* calculate file offset */
|
|
pos += sectsize * (dsk_unit[cur_dsk].u5 - sector_base);
|
|
err = sim_fseek(dsk_unit[cur_dsk].fileref, pos, SEEK_SET); /* seek to offset */
|
|
if (err) {
|
|
sim_printf("fdccmd: Seek error in write command\n");
|
|
return SCPE_IOERR;
|
|
}
|
|
dsk_unit[cur_dsk].u3 |= DRQ;/* set DRQ */
|
|
wrt_flag = 1; /* RSV - set write flag */
|
|
dsk_unit[cur_dsk].pos = 0; /* clear counter */
|
|
}
|
|
break;
|
|
case 0x1B: //seek command type I
|
|
dsk_unit[cur_dsk].u4 = fdcbyte; /* set track */
|
|
dsk_unit[cur_dsk].u3 &= ~(BUSY | DRQ); /* clear flags */
|
|
break;
|
|
case 0x0B: //restore command type I
|
|
dsk_unit[cur_dsk].u4 = 0; /* home the drive */
|
|
dsk_unit[cur_dsk].u3 &= ~(BUSY | DRQ | RECNF); /* clear flags */
|
|
break;
|
|
case 0xF0: //write track command type III
|
|
case 0xF4: //write track command type III
|
|
break;
|
|
case 0xD0: //Force Interrupt - terminate current command
|
|
dsk_unit[cur_dsk].u3 &= ~(BUSY | DRQ); /* clear flags */
|
|
break;
|
|
default:
|
|
sim_printf("Unknown FDC command %02X\n\r", data);
|
|
}
|
|
} else { /* read status from fdc */
|
|
val = dsk_unit[cur_dsk].u3; /* set return value */
|
|
if (index_countdown) { // RSV - Handle INDEX flag
|
|
index_countdown--;
|
|
// if index countdoen expires, set index flag in status returned to cpu
|
|
if (index_countdown==0) val |= INDEX;
|
|
}
|
|
}
|
|
return val;
|
|
}
|
|
|
|
/* WD 1797 FDC track register routine */
|
|
|
|
int32 fdctrk(int32 io, int32 data)
|
|
{
|
|
if (io) {
|
|
dsk_unit[cur_dsk].u3 &= ~(RECNF); /* reset RECNF flag */
|
|
dsk_unit[cur_dsk].u4 = data & BYTEMASK;
|
|
}
|
|
return dsk_unit[cur_dsk].u4;
|
|
}
|
|
|
|
/* WD 1797 FDC sector register routine */
|
|
|
|
int32 fdcsec(int32 io, int32 data)
|
|
{
|
|
if (io) {
|
|
dsk_unit[cur_dsk].u3 &= ~(RECNF); /* reset RECNF flag */
|
|
dsk_unit[cur_dsk].u5 = data & BYTEMASK;
|
|
if (dsk_unit[cur_dsk].u5 < sector_base) //RSV - force to sector 1
|
|
dsk_unit[cur_dsk].u5 = sector_base;
|
|
return 0;
|
|
}
|
|
return dsk_unit[cur_dsk].u5;
|
|
}
|
|
|
|
/* WD 1797 FDC data register routine */
|
|
|
|
int32 fdcdata(int32 io, int32 data)
|
|
{
|
|
int32 val, err;
|
|
|
|
if (cur_dsk >= NUM_DISK) // RSV - illegal disk
|
|
return 0;
|
|
if (io) { /* write byte to fdc */
|
|
fdcbyte = data; /* save for seek */
|
|
if (dsk_unit[cur_dsk].pos < (t_addr) sectsize) { /* copy bytes to buffer */
|
|
*((uint8 *)(dsk_unit[cur_dsk].filebuf) + dsk_unit[cur_dsk].pos) = data; /* byte into buffer */
|
|
dsk_unit[cur_dsk].pos++; /* step counter */
|
|
if (dsk_unit[cur_dsk].pos == sectsize) {
|
|
dsk_unit[cur_dsk].u3 &= ~(BUSY | DRQ);
|
|
if (wrt_flag) { /* if initiated by FDC write command */
|
|
sim_fwrite(dsk_unit[cur_dsk].filebuf, sectsize, 1, dsk_unit[cur_dsk].fileref); /* write it */
|
|
wrt_flag = 0; /* clear write flag */
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
} else { /* read byte from fdc */
|
|
if (dsk_unit[cur_dsk].pos < (t_addr) sectsize) { /* copy bytes from buffer */
|
|
val = *((uint8 *)(dsk_unit[cur_dsk].filebuf) + dsk_unit[cur_dsk].pos) & BYTEMASK;
|
|
dsk_unit[cur_dsk].pos++; /* step counter */
|
|
if (dsk_unit[cur_dsk].pos == sectsize) { // sector finished
|
|
if ((multiple_sector) && (dsk_unit[cur_dsk].u5-sector_base < spt-1)) { // read multiple in progress
|
|
dsk_unit[cur_dsk].u5++;
|
|
err = sim_fread(dsk_unit[cur_dsk].filebuf, sectsize, 1, dsk_unit[cur_dsk].fileref); /* read in buffer */
|
|
if (err != 1) {
|
|
sim_printf("fdccmd: File error in read command\n");
|
|
return SCPE_IOERR;
|
|
}
|
|
dsk_unit[cur_dsk].pos = 0;
|
|
} else { // RSV - handle multiple sector disk read
|
|
dsk_unit[cur_dsk].u5++;
|
|
dsk_unit[cur_dsk].u3 &= ~(BUSY | DRQ); /* clear flags */
|
|
if (multiple_sector) {
|
|
multiple_sector=0;
|
|
}
|
|
}
|
|
}
|
|
return val;
|
|
} else
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* end of dc-4.c */
|