--- /dev/null
+/*
+ * low-level functions for the SWIM floppy controller
+ *
+ * needs assembly language because is very timing dependent
+ * this controller exists only on macintosh 680x0 based
+ *
+ * Copyright (C) 2004,2008 Laurent Vivier <Laurent@lvivier.info>
+ *
+ * based on Alastair Bridgewater SWIM analysis, 2001
+ * based on netBSD IWM driver (c) 1997, 1998 Hauke Fath.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * 2004-08-21 (lv) - Initial implementation
+ * 2008-11-05 (lv) - add get_swim_mode
+ */
+
+ .equ write_data, 0x0000
+ .equ write_mark, 0x0200
+ .equ write_CRC, 0x0400
+ .equ write_parameter,0x0600
+ .equ write_phase, 0x0800
+ .equ write_setup, 0x0a00
+ .equ write_mode0, 0x0c00
+ .equ write_mode1, 0x0e00
+ .equ read_data, 0x1000
+ .equ read_mark, 0x1200
+ .equ read_error, 0x1400
+ .equ read_parameter, 0x1600
+ .equ read_phase, 0x1800
+ .equ read_setup, 0x1a00
+ .equ read_status, 0x1c00
+ .equ read_handshake, 0x1e00
+
+ .equ o_side, 0
+ .equ o_track, 1
+ .equ o_sector, 2
+ .equ o_size, 3
+ .equ o_crc0, 4
+ .equ o_crc1, 5
+
+ .equ seek_time, 30000
+ .equ max_retry, 40
+ .equ sector_size, 512
+
+ .global swim_read_sector_header
+swim_read_sector_header:
+ link %a6, #0
+ moveml %d1-%d5/%a0-%a4,%sp@-
+ movel %a6@(0x0c), %a4
+ bsr mfm_read_addrmark
+ moveml %sp@+, %d1-%d5/%a0-%a4
+ unlk %a6
+ rts
+
+sector_address_mark:
+ .byte 0xa1, 0xa1, 0xa1, 0xfe
+sector_data_mark:
+ .byte 0xa1, 0xa1, 0xa1, 0xfb
+
+mfm_read_addrmark:
+ movel %a6@(0x08), %a3
+ lea %a3@(read_handshake), %a2
+ lea %a3@(read_mark), %a3
+ moveq #-1, %d0
+ movew #seek_time, %d2
+
+wait_header_init:
+ tstb %a3@(read_error - read_mark)
+ moveb #0x18, %a3@(write_mode0 - read_mark)
+ moveb #0x01, %a3@(write_mode1 - read_mark)
+ moveb #0x01, %a3@(write_mode0 - read_mark)
+ tstb %a3@(read_error - read_mark)
+ moveb #0x08, %a3@(write_mode1 - read_mark)
+
+ lea sector_address_mark, %a0
+ moveq #3, %d1
+
+wait_addr_mark_byte:
+
+ tstb %a2@
+ dbmi %d2, wait_addr_mark_byte
+ bpl header_exit
+
+ moveb %a3@, %d3
+ cmpb %a0@+, %d3
+ dbne %d1, wait_addr_mark_byte
+ bne wait_header_init
+
+ moveq #max_retry, %d2
+
+amark0: tstb %a2@
+ dbmi %d2, amark0
+ bpl signal_nonyb
+
+ moveb %a3@, %a4@(o_track)
+
+ moveq #max_retry, %d2
+
+amark1: tstb %a2@
+ dbmi %d2, amark1
+ bpl signal_nonyb
+
+ moveb %a3@, %a4@(o_side)
+
+ moveq #max_retry, %d2
+
+amark2: tstb %a2@
+ dbmi %d2, amark2
+ bpl signal_nonyb
+
+ moveb %a3@, %a4@(o_sector)
+
+ moveq #max_retry, %d2
+
+amark3: tstb %a2@
+ dbmi %d2, amark3
+ bpl signal_nonyb
+
+ moveb %a3@, %a4@(o_size)
+
+ moveq #max_retry, %d2
+
+crc0: tstb %a2@
+ dbmi %d2, crc0
+ bpl signal_nonyb
+
+ moveb %a3@, %a4@(o_crc0)
+
+ moveq #max_retry, %d2
+
+crc1: tstb %a2@
+ dbmi %d2, crc1
+ bpl signal_nonyb
+
+ moveb %a3@, %a4@(o_crc1)
+
+ tstb %a3@(read_error - read_mark)
+
+header_exit:
+ moveq #0, %d0
+ moveb #0x18, %a3@(write_mode0 - read_mark)
+ rts
+signal_nonyb:
+ moveq #-1, %d0
+ moveb #0x18, %a3@(write_mode0 - read_mark)
+ rts
+
+ .global swim_read_sector_data
+swim_read_sector_data:
+ link %a6, #0
+ moveml %d1-%d5/%a0-%a5,%sp@-
+ movel %a6@(0x0c), %a4
+ bsr mfm_read_data
+ moveml %sp@+, %d1-%d5/%a0-%a5
+ unlk %a6
+ rts
+
+mfm_read_data:
+ movel %a6@(0x08), %a3
+ lea %a3@(read_handshake), %a2
+ lea %a3@(read_data), %a5
+ lea %a3@(read_mark), %a3
+ movew #seek_time, %d2
+
+wait_data_init:
+ tstb %a3@(read_error - read_mark)
+ moveb #0x18, %a3@(write_mode0 - read_mark)
+ moveb #0x01, %a3@(write_mode1 - read_mark)
+ moveb #0x01, %a3@(write_mode0 - read_mark)
+ tstb %a3@(read_error - read_mark)
+ moveb #0x08, %a3@(write_mode1 - read_mark)
+
+ lea sector_data_mark, %a0
+ moveq #3, %d1
+
+ /* wait data address mark */
+
+wait_data_mark_byte:
+
+ tstb %a2@
+ dbmi %d2, wait_data_mark_byte
+ bpl data_exit
+
+ moveb %a3@, %d3
+ cmpb %a0@+, %d3
+ dbne %d1, wait_data_mark_byte
+ bne wait_data_init
+
+ /* read data */
+
+ tstb %a3@(read_error - read_mark)
+
+ movel #sector_size-1, %d4 /* sector size */
+read_new_data:
+ movew #max_retry, %d2
+read_data_loop:
+ moveb %a2@, %d5
+ andb #0xc0, %d5
+ dbne %d2, read_data_loop
+ beq data_exit
+ moveb %a5@, %a4@+
+ andb #0x40, %d5
+ dbne %d4, read_new_data
+ beq exit_loop
+ moveb %a5@, %a4@+
+ dbra %d4, read_new_data
+exit_loop:
+
+ /* read CRC */
+
+ movew #max_retry, %d2
+data_crc0:
+
+ tstb %a2@
+ dbmi %d2, data_crc0
+ bpl data_exit
+
+ moveb %a3@, %d5
+
+ moveq #max_retry, %d2
+
+data_crc1:
+
+ tstb %a2@
+ dbmi %d2, data_crc1
+ bpl data_exit
+
+ moveb %a3@, %d5
+
+ tstb %a3@(read_error - read_mark)
+
+ moveb #0x18, %a3@(write_mode0 - read_mark)
+
+ /* return number of bytes read */
+
+ movel #sector_size, %d0
+ addw #1, %d4
+ subl %d4, %d0
+ rts
+data_exit:
+ moveb #0x18, %a3@(write_mode0 - read_mark)
+ moveq #-1, %d0
+ rts
Code Review / kvmfornfv.git / blobdiff