Mercurial > hg > Members > kono > nitros9-code

comparison level1/modules/dw4read.asm @ 2576:35c61c91bc29

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added 6309 code from Darren
author boisy
date Mon, 16 May 2011 00:57:24 +0000
parents 236dd2507569
children b839b516cb35
comparison
equal deleted inserted replaced
2575:a9a5be5114b2 2576:35c61c91bc29
1 IFNE H6309-1
2
3 *******************************************************
4 *
5 * DWRead - 6309 native Turbo Edition 115k / 230k
6 * Receive a response from the DriveWire server.
7 * Times out if no data received within 1.3 (0.66) seconds.
8 *
9 * THIS VERSION REQUIRES ONE OR MORE SYNC BYTES
10 * WHERE THE THE FINAL SYNC BYTE IS $C0 AND ANY
11 * PRECEDING SYNC BYTES ARE $FF.
12 *
13 * THE DATA BYTES MUST BE TRANSMITTED IN REVERSE
14 * BIT ORDER (MOST-SIGNIFICANT FIRST).
15 *
16 * Serial data format: 8-N-2 (TWO STOP BITS MANDATORY)
17 *
18 * Entry:
19 * X = storage address for incoming data
20 * Y = number of bytes requested
21 *
22 * Exit:
23 * CC = Z set on success, cleared on timeout
24 * Y = checksum
25 * U is preserved
26 * All others clobbered
27 *
28 BBIN equ $FF22 ; bit banger input port
29
30 DWRead clra ; ACCA = 0, clear Carry
31 pshs u,dp,a,cc ; save registers (A allocates space for status)
32 orcc #$50 ; mask interrupts
33 deca ; select hardware page..
34 tfr a,dp ; ..as the direct page
35 ldu #BBIN ; point U at input port
36 tfr y,w ; W = request count
37 leay ,x ; Y = storage ptr
38 ldx #0 ; initialize timeout counter
39 stx <$FF92 ; disable GIME interrupts
40 ldd <$FF92 ; clear spurious interrupts
41
42 * Turn off PIA interrupt sources except for the CD input pin.
43 lda <$FF01 ; save PIA 0 controls on the stack
44 ldb <$FF03
45 pshs d
46 andd #$FCFC ; clear IRQ enables
47 sta <$FF01 ; set new control state for PIA 0
48 stb <$FF03
49 lda <$FF00 ; ensure that IRQ outputs are cleared
50 ldb <$FF02
51 lda <$FF21 ; save PIA 1 controls on the stack
52 ldb <$FF23
53 pshs d
54 andd #$FCFC ; clear FIRQ enables
55 inca ; set CD FIRQ enable
56 sta <$FF21 ; set new control state for PIA 1
57 stb <$FF23
58
59 * Wait for Sync Byte(s) or Timeout
60 sync1 ldd #$0102 ; ACCA = serial in mask, ACCB = shift counter
61 sync2 bita ,u ; sample input
62 beq sync3 ; branch if low
63 leax -1,x ; decrement timeout counter
64 bne sync1 ; loop if timeout has not expired
65 bra rxDone ; exit due to timeout
66 sync3 lsrb ; have there been 2 consecutive low samples?
67 bcc sync2 ; keep waiting if no
68 ldx #0 ; initialize checksum
69 sync4 bita ,u ; sample input
70 bne rxByte ; branch if input has returned hi
71 rorb ; bump secondary timeout counter
72 bcc sync4 ; branch if not timeout
73 bra rxDone ; exit due to timeout
74
75 * Byte receiver loop
76 rxByte lda <$FF20 ; reset FIRQ
77 sync ; wait for start bit
78 leau ,u
79 lda ,u ; bit 0
80 lsra
81 rolb
82 lda ,u++ ; bit 1
83 lsra
84 rolb
85 lda -2,u ; bit 2
86 lsra
87 rolb
88 lda ,--u ; bit 3
89 lsra
90 rolb
91 lda ,u++ ; bit 4
92 lsra
93 rolb
94 lda ,--u ; bit 5
95 lsra
96 rolb
97 lda ,u+ ; bit 6
98 lsra
99 rolb
100 nop
101 lda ,-u ; bit 7
102 lsra
103 rolb
104 abx ; update checksum
105 stb ,y+ ; put byte to storage
106 decw ; decrement counter
107 bne rxByte ; loop if more bytes to read
108 clra ; status = SUCCESS
109 rxDone sta 5,s ; store status on stack
110
111 * Restore previous PIA control settings
112 puls d ; restore original PIA 1 controls
113 sta <$FF21
114 stb <$FF23
115 puls d ; restore original PIA 0 controls
116 sta <$FF01
117 stb <$FF03
118 lda <$FF20 ; make sure the CD FIRQ has been cleared
119
120 IFNE NITROS9-1
121 * Restoration of GIME interrupts in NitrOS9
122 ldd >D.IRQER ; retrieve shadow copy of IRQ/FIRQ enable regs
123 std <$FF92 ; restore GIME
124 ldd <$FF92 ; clear spurious interrupts
125 ENDIF
126
127 * Clean up and return
128 leay ,x ; return checksum in Y
129 puls cc,a,dp,u ; ACCA = status; restore IRQ masks, DP and U
130 tsta ; set CC.Z if status = SUCCESS
131 rts ; return
132
133 ELSE
134
1 ******************************************************* 135 *******************************************************
2 * 136 *
3 * DWRead - 6809 Turbo Edition 115k / 230k 137 * DWRead - 6809 Turbo Edition 115k / 230k
4 * Receive a response from the DriveWire server. 138 * Receive a response from the DriveWire server.
5 * Times out if no data received within 1.3 (0.66) seconds. 139 * Times out if no data received within 1.3 (0.66) seconds.
117 puls d ; restore original PIA 0 controls 251 puls d ; restore original PIA 0 controls
118 sta <$FF01 252 sta <$FF01
119 stb <$FF03 253 stb <$FF03
120 lda <$FF20 ; make sure the CD FIRQ has been cleared 254 lda <$FF20 ; make sure the CD FIRQ has been cleared
121 255
122 IF NITROS 256 IFNE NITROS9-1
123 * Restoration of GIME interrupts in NitrOS9 257 * Restoration of GIME interrupts in NitrOS9
124 ldd >D.IRQER ; retrieve shadow copy of IRQ/FIRQ enable regs 258 ldd >D.IRQER ; retrieve shadow copy of IRQ/FIRQ enable regs
125 std <$FF92 ; restore GIME 259 std <$FF92 ; restore GIME
126 ldd <$FF92 ; clear spurious interrupts 260 ldd <$FF92 ; clear spurious interrupts
127 ENDIF 261 ENDIF
128 262
129 * Checksum computation 263 * Checksum computation
130 clrb ; initialize checksum LSB 264 clrb ; initialize checksum LSB
131 puls cc,a,dp,x,y ; restore IRQ masks, DP and the caller params 265 puls cc,a,dp,x,y ; restore IRQ masks, DP and the caller params
132 tsta ; timeout error? 266 tsta ; timeout error?
136 leay -1,y ; decrement counter 270 leay -1,y ; decrement counter
137 bne sumLoop ; loop until all data summed 271 bne sumLoop ; loop until all data summed
138 andcc #$FE ; clear carry (no framing error) 272 andcc #$FE ; clear carry (no framing error)
139 rxExit tfr d,y ; move checksum into Y without affecting CC.Z 273 rxExit tfr d,y ; move checksum into Y without affecting CC.Z
140 rts ; return 274 rts ; return
275
276 ENDC