source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Device/Serial/SerialCommand.asm@ 195

Last change on this file since 195 was 181, checked in by krille_n_@…, 13 years ago

Changes to all parts of the project:

  • Size optimizations.
  • Added a define (EXCLUDE_FROM_XTIDECFG) to exclude unused library code from XTIDECFG.
  • Tried to minimize time spent with interrupts disabled.
  • Some minor attempts to improve speed (reordering instructions etc).
  • Tried to improve readability, did some cleanup and fixed some errors in comments.
File size: 15.3 KB
RevLine 
[150]1; Project name : XTIDE Universal BIOS
2; Description : Serial Device Command functions.
3
4; Section containing code
5SECTION .text
6
[179]7;--------------- UART Equates -----------------------------
8;
9; Serial Programming References:
10; http://en.wikibooks.org/wiki/Serial_Programming
11;
[181]12
[179]13SerialCommand_UART_base EQU 0
14SerialCommand_UART_transmitByte EQU 0
15SerialCommand_UART_receiveByte EQU 0
16SerialCommand_UART_divisorLow EQU 0
[181]17; Values for UART_divisorLow:
[179]18; 60h = 1200, 30h = 2400, 18h = 4800, 0ch = 9600, 6 = 19200, 3 = 38400, 2 = 57600, 1 = 115200
19
20SerialCommand_UART_divisorLow_startingBaud EQU 030h
21; We support 4 baud rates, starting here going higher and skipping every other baud rate
22; Starting with 30h, that means 30h (1200 baud), 0ch (9600 baud), 3 (38400 baud), and 1 (115200 baud)
23; Note: hardware baud multipliers (2x, 4x) will impact the final baud rate and are not known at this level
24
[181]25SerialCommand_UART_interruptEnable EQU 1
[179]26SerialCommand_UART_divisorHigh EQU 1
27; UART_divisorHigh is zero for all speeds including and above 1200 baud
28
29SerialCommand_UART_interruptIdent EQU 2
30SerialCommand_UART_FIFOControl EQU 2
31
32SerialCommand_UART_lineControl EQU 3
[181]33
[179]34SerialCommand_UART_modemControl EQU 4
35
36SerialCommand_UART_lineStatus EQU 5
37
38SerialCommand_UART_modemStatus EQU 6
39
40SerialCommand_UART_scratch EQU 7
41
[181]42SerialCommand_PackedPortAndBaud_StartingPort EQU 240h
[179]43SerialCommand_PackedPortAndBaud_PortMask EQU 0fch ; upper 6 bits - 240h through 438h
44SerialCommand_PackedPortAndBaud_BaudMask EQU 3 ; lower 2 bits - 4 baud rates
45
46SerialCommand_Protocol_Write EQU 3
47SerialCommand_Protocol_Read EQU 2
48SerialCommand_Protocol_Inquire EQU 0
49SerialCommand_Protocol_Header EQU 0a0h
[181]50
[150]51;--------------------------------------------------------------------
[179]52; SerialCommand_OutputWithParameters
[150]53; Parameters:
[179]54; BH: Non-zero if 48-bit addressing used
55; (ignored at present as 48-bit addressing is not supported)
56; BL: IDE Status Register bit to poll after command
57; (ignored at present, since there is no IDE status register to poll)
58; ES:SI: Ptr to buffer (for data transfer commands)
59; DS:DI: Ptr to DPT (in RAMVARS segment)
60; SS:BP: Ptr to IDEREGS_AND_INTPACK
[150]61; Returns:
62; AH: INT 13h Error Code
63; CF: Cleared if success, Set if error
64; Corrupts registers:
[179]65; AL, BX, CX, DX, (ES:SI for data transfer commands)
[150]66;--------------------------------------------------------------------
67ALIGN JUMP_ALIGN
[179]68SerialCommand_OutputWithParameters:
[181]69
[179]70 mov ah,(SerialCommand_Protocol_Header | SerialCommand_Protocol_Read)
[181]71
[179]72 mov al,[bp+IDEPACK.bCommand]
[150]73
[179]74 cmp al,20h ; Read Sectors IDE command
75 jz .readOrWrite
76 inc ah ; now SerialCommand_Protocol_Write
77 cmp al,30h ; Write Sectors IDE command
78 jz .readOrWrite
[181]79
[179]80; all other commands return success
81; including function 0ech which should return drive information, this is handled with the identify functions
82 xor ah,ah ; also clears carry
83 ret
[181]84
85.readOrWrite:
[179]86 mov [bp+IDEPACK.bFeatures],ah ; store protocol command
[181]87
88 mov dl, byte [di+DPT.bSerialPortAndBaud]
89
[179]90; fall-through
[150]91
92;--------------------------------------------------------------------
[179]93; SerialCommand_OutputWithParameters_DeviceInDL
[150]94; Parameters:
[181]95; AH: Protocol Command
[179]96; DL: Packed I/O port and baud rate
[150]97; ES:SI: Ptr to buffer (for data transfer commands)
98; SS:BP: Ptr to IDEREGS_AND_INTPACK
99; Returns:
100; AH: INT 13h Error Code
101; CF: Cleared if success, Set if error
102; Corrupts registers:
103; AL, BX, CX, DX, (ES:SI for data transfer commands)
[181]104;--------------------------------------------------------------------
[179]105SerialCommand_OutputWithParameters_DeviceInDL:
[181]106
[179]107 push si
108 push di
109 push bp
110 push es
111
[181]112;
[179]113; Unpack I/O port and baud from DPT
114; Port to DX more or less for the remainder of the routine
115; Baud in CH until UART initialization is complete
116;
117 mov cl, dl
[181]118
[179]119 and cl, SerialCommand_PackedPortAndBaud_BaudMask
120 shl cl, 1
121 mov ch, SerialCommand_UART_divisorLow_startingBaud
122 shr ch, cl
123 adc ch, 0
124
125 and dl, SerialCommand_PackedPortAndBaud_PortMask
[181]126 mov dh, 0
[179]127 shl dx, 1
128 add dx, SerialCommand_PackedPortAndBaud_StartingPort
129
130;
131; Buffer is referenced through ES:DI throughout, since we need to store faster than we read
[181]132;
[179]133 mov di,si
134
135 mov al,[bp+IDEPACK.bSectorCount]
136
137;
138; Command byte and sector count live at the top of the stack, pop/push are used to access
[181]139;
[179]140 push ax
141
[181]142; cld ; Shouldn't be needed. DF has already been cleared (line 24, Int13h.asm)
143
[179]144;----------------------------------------------------------------------
145;
146; Initialize UART
147;
[181]148; We do this each time since DOS (at boot) or another program may have
[179]149; decided to reprogram the UART
150;
151 push dx
[181]152
[179]153 mov al,83h
154 add dl,SerialCommand_UART_lineControl
155 out dx,al
156
157 mov al,ch
158 pop dx ; divisor low
159 out dx,al
160
161 xor ax,ax
162 inc dx ; divisor high
163 push dx
164 out dx,al
165
166 mov al,047h
167 inc dx ; fifo
[181]168 out dx,al
[179]169
170 mov al,03h
171 inc dx ; linecontrol
172 out dx,al
173
174 mov al,0bh
175 inc dx ; modemcontrol
176 out dx,al
177
178 pop dx ; base, interrupts disabled
179 xor ax,ax
180 out dx,al
181 dec dx
182
183;----------------------------------------------------------------------
184;
185; Send Command
186;
187; Sends first six bytes of IDEREGS_AND_INTPACK as the command
188;
189 call Registers_NormalizeESDI
190
191 push es ; save off real buffer location
192 push di
[181]193
194 mov di,bp ; point to IDEREGS for command dispatch;
[179]195 push ss
196 pop es
197
198 xor si,si ; initialize checksum for write
[181]199 dec si
[179]200 mov bp,si
201
202 mov bl,03h ; writing 3 words
[181]203
[179]204 call SerialCommand_WriteProtocol
205
206 pop di ; restore real buffer location
207 pop es
208
209 pop ax ; load command byte (done before call to .nextSector on subsequent iterations)
210 push ax
211
212;
213; Top of the read/write loop, one iteration per sector
[181]214;
[179]215.nextSector:
216 xor si,si ; initialize checksum for read or write
217 dec si
218 mov bp,si
219
220 mov bx,0100h
[181]221
[179]222 shr ah,1 ; command byte, are we doing a write?
223 jnc .readSector
224 call SerialCommand_WriteProtocol
[181]225
[179]226 xor bx,bx
227
228.readSector:
229 mov cx,bx
230 inc cx
[181]231
[179]232 mov bl,dl ; setup bl with proper values for read loop (bh comes later)
233
234;----------------------------------------------------------------------
235;
236; Timeout
237;
238; During read, we first poll in a tight loop, interrupts off, for the next character to come in
239; If that loop completes, then we assume there is a long delay involved, turn interrupts back on
240; and wait for a given number of timer ticks to pass.
241;
242; To save code space, we use the contents of DL to decide which byte in the word to return for reading.
243;
244.readTimeout:
245 push cx
246 xor cx,cx
[181]247.readTimeoutLoop:
[179]248 push dx
249 or dl,SerialCommand_UART_lineStatus
250 in al,dx
251 pop dx
252 shr al,1
253 jc .readTimeoutComplete
254 loop .readTimeoutLoop
255 sti
256 mov bh,1
257 call SerialCommand_WaitAndPoll_Init
[181]258 cli
[179]259.readTimeoutComplete:
260 mov bh,bl
261 or bh,SerialCommand_UART_lineStatus
[181]262
[179]263 pop cx
264 test dl,1
265 jz .readByte1Ready
266 jmp .readByte2Ready
267
268;----------------------------------------------------------------------------
269;
270; Read Block (without interrupts, used when there is a FIFO, high speed)
271;
[181]272; NOTE: This loop is very time sensitive. Literally, another instruction
[179]273; cannot be inserted into this loop without us falling behind at high
[181]274; speed (460.8K baud) on a 4.77Mhz 8088, making it hard to receive
[179]275; a full 512 byte block.
276;
[181]277.readLoop:
278 stosw ; store word in caller's data buffer
279
[179]280 add bp, ax ; update Fletcher's checksum
281 adc bp, 0
282 add si, bp
283 adc si, 0
284
[181]285 mov dl,bh
286 in al,dx
[179]287 shr al,1 ; data ready (byte 1)?
[181]288 mov dl,bl ; get ready to read data
[179]289 jnc .readTimeout ; nope not ready, update timeouts
[181]290
291;
[179]292; Entry point after initial timeout. We enter here so that the checksum word
293; is not stored (and is left in AX after the loop is complete).
[181]294;
295.readByte1Ready:
[179]296 in al, dx ; read data byte 1
297
298 mov ah, al ; store byte in ah for now
[181]299
[179]300;
[181]301; note the placement of this reset of dl to bh, and that it is
302; before the return, which is assymetric with where this is done
303; above for byte 1. The value of dl is used by the timeout routine
304; to know which byte to return to (.read_byte1_ready or
[179]305; .read_byte2_ready)
306;
[181]307 mov dl,bh
308
[179]309 in al,dx
310 shr al,1 ; data ready (byte 2)?
311 jnc .readTimeout
[181]312.readByte2Ready:
313 mov dl,bl
[179]314 in al, dx ; read data byte 2
315
316 xchg al, ah ; ah was holding byte 1, reverse byte order
[181]317
[179]318 loop .readLoop
319
[181]320 sti ; interrupts back on ASAP, if we turned them off
321
[179]322;
323; Compare checksums
[181]324;
[179]325 xor bp,si
326 cmp ax,bp
327 jnz SerialCommand_OutputWithParameters_Error
328
[181]329
[179]330;----------------------------------------------------------------------
[181]331;
[179]332; Clear read buffer
333;
334; In case there are extra characters or an error in the FIFO, clear it out.
[181]335; In theory the initialization of the UART registers above should have
[179]336; taken care of this, but I have seen cases where this is not true.
337;
338.clearBuffer:
[181]339 mov dl,bh
[179]340 in al,dx
[181]341 mov dl,bl
[179]342 test al,08fh
343 jz .clearBufferComplete
344 shr al,1
[181]345 in al,dx
[179]346 jc .clearBuffer ; note CF from shr above
347 jmp SerialCommand_OutputWithParameters_Error
[181]348
349.clearBufferComplete:
[179]350 pop ax ; sector count and command byte
351 dec al ; decrememnt sector count
352 push ax ; save
353 jz SerialCommand_OutputWithParameters_ReturnCodeInALCF ; CF clear from .clearBuffer test above
[181]354
[179]355 cli ; interrupts back off for ACK byte to host
356 ; (host could start sending data immediately)
357 out dx,al ; ACK with next sector number
[181]358
[179]359 jmp .nextSector ; all is well, time for next sector
360
361;---------------------------------------------------------------------------
362;
363; Cleanup, error reporting, and exit
364;
[181]365
366;
[179]367; Used in situations where a call is underway, such as with SerialCommand_WaitAndPoll
[181]368;
[179]369SerialCommand_OutputWithParameters_ErrorAndPop2Words:
370 pop ax
371 pop ax
372
[181]373SerialCommand_OutputWithParameters_Error:
374 stc
[179]375 mov al,1
376
[181]377SerialCommand_OutputWithParameters_ReturnCodeInALCF:
378 sti
[179]379 mov ah,al
380
381 pop bp ; recover ax from stack, throw away
382
383 pop es
384 pop bp
385 pop di
386 pop si
387
388 ret
389
[150]390;--------------------------------------------------------------------
[179]391; SerialCommand_WaitAndPoll
392;
393; Parameters:
394; BH: UART_LineStatus bit to test (20h for write, or 1h for read)
395; DX: Port address (OK if already incremented to UART_lineStatus)
396; Stack: 2 words on the stack below the command/count word
397; Returns:
398; Returns when desired UART_LineStatus bit is cleared
399; Jumps directly to error exit if timeout elapses (and cleans up stack)
[181]400; Corrupts registers:
[179]401; CX, flags
402;--------------------------------------------------------------------
403
404SerialCommand_WaitAndPoll_SoftDelayTicks EQU 20
405
[181]406ALIGN JUMP_ALIGN
[179]407SerialCommand_WaitAndPoll_Init:
408 mov cl,SerialCommand_WaitAndPoll_SoftDelayTicks
409 call Timer_InitializeTimeoutWithTicksInCL
410; fall-through
[181]411
[179]412SerialCommand_WaitAndPoll:
413 call Timer_SetCFifTimeout
414 jc SerialCommand_OutputWithParameters_ErrorAndPop2Words
415 push dx
416 push ax
417 or dl,SerialCommand_UART_lineStatus
418 in al,dx
419 test al,bh
420 pop ax
421 pop dx
422 jz SerialCommand_WaitAndPoll
423; fall-through
[181]424
425SerialCommand_WaitAndPoll_Done:
[179]426 ret
427
428;--------------------------------------------------------------------
429; SerialCommand_WriteProtocol
430;
431; Parameters:
432; ES:DI: Ptr to buffer
433; BL: Words to write (1-255, or 0=256)
434; BP/SI: Initialized for Checksum (-1 in each)
435; DX: I/O Port
436; Returns:
437; BP/SI: Checksum for written bytes, compared against ACK from server in .readLoop
438; Corrupts registers:
439; AX, BX, CX, DI
440;--------------------------------------------------------------------
[150]441ALIGN JUMP_ALIGN
[179]442SerialCommand_WriteProtocol:
443 mov bh,20h
[181]444
[179]445.writeLoop:
446 test bh,1
447 jnz SerialCommand_WaitAndPoll_Done
[181]448
[179]449 mov ax,[es:di] ; fetch next word
450 inc di
451 inc di
[181]452
[179]453 add bp,ax ; update checksum
454 adc bp,0
455 add si,bp
456 adc si,0
[150]457
[179]458.writeLoopChecksum:
459 call SerialCommand_WaitAndPoll_Init
[181]460
[179]461 out dx,al ; output first byte
[150]462
[179]463 call SerialCommand_WaitAndPoll
[181]464
[179]465 mov al,ah ; output second byte
466 out dx,al
467
468 dec bl
469 jnz .writeLoop
[181]470
[179]471 inc bh
[181]472
[179]473 mov ax,bp ; merge checksum for possible write (last loop)
[181]474 xor ax,si
475
[179]476 jmp .writeLoopChecksum
477
478
479; To return the port number and baud rate to the FinalizeDPT routine, we
480; stuff the value in a "vendor" specific area of the 512-byte IdentifyDevice
481; sector.
482;
483SerialCommand_IdentifyDevice_PackedPortAndBaud equ (157*2)
484
485;--------------------------------------------------------------------
486; SerialCommand_IdentifyDeviceToBufferInESSIwithDriveSelectByteInBH
487; Parameters:
488; BH: Drive Select byte for Drive and Head Select Register
489; DS: Segment to RAMVARS
490; ES:SI: Ptr to buffer to receive 512-byte IDE Information
491; CS:BP: Ptr to IDEVARS
492; Returns:
493; AH: INT 13h Error Code
494; CF: Cleared if success, Set if error
495; Corrupts registers:
496; AL, BL, CX, DX, SI, DI, ES
497;--------------------------------------------------------------------
498ALIGN JUMP_ALIGN
499SerialCommand_IdentifyDeviceToBufferInESSIwithDriveSelectByteInBH:
500
501 mov dx,[cs:bp+IDEVARS.wPortCtrl]
502 inc dx
[181]503 dec dx
[179]504 jz SerialCommand_AutoSerial
505
506; fall-through
[181]507SerialCommand_IdentifyDeviceInDL_DriveInBH:
[179]508
509 push bp ; setup fake IDEREGS_AND_INTPACK
510
511 push dx
512
513 mov cl,1 ; 1 sector to move
514 push cx
515
516 mov bl,0a0h ; protocol command to ah and onto stack with bh
517 mov ah,bl
[181]518
[179]519 push bx
520
521 mov bp,sp
522
523 call SerialCommand_OutputWithParameters_DeviceInDL
524
525 pop bx
[181]526
527 pop cx
[179]528 pop dx
529
530 pop bp
531
[181]532; place packed port/baud in vendor area of packet, read by FinalizeDPT
533 mov byte [es:si+SerialCommand_IdentifyDevice_PackedPortAndBaud], dl
[179]534
535 ret
536
537;----------------------------------------------------------------------
538;
539; SerialCommand_AutoSerial
540;
541; When the SerialAuto IDEVARS entry is used, scans the COM ports on the machine for a possible serial connection.
[181]542;
543
[179]544SerialCommand_ScanPortAddresses: db 0b8h, 0f8h, 0bch, 0bah, 0fah, 0beh, 0feh, 0
545; Corresponds to I/O port: 3f8, 2f8, 3e8, 2e8, 2f0, 3e0, 2e0, 260, 368, 268, 360, 270
546; COM Assignments: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
547
[181]548ALIGN JUMP_ALIGN
549SerialCommand_AutoSerial:
[179]550 mov di,SerialCommand_ScanPortAddresses-1
[181]551
[179]552.nextPort:
553 inc di ; load next port address
554 mov dl,[cs:di]
[181]555
[179]556 mov dh,0 ; shift from one byte to two
[181]557 eSHL_IM dx, 2
[179]558 jz .exitNotFound
559
560;
561; Test for COM port presence, write to and read from registers
[181]562;
563 push dx
[179]564 add dl,SerialCommand_UART_lineControl
565 mov al, 09ah
566 out dx, al
567 in al, dx
568 pop dx
569 cmp al, 09ah
[181]570 jnz .nextPort
[179]571
572 mov al, 0ch
573 out dx, al
574 in al, dx
575 cmp al, 0ch
576 jnz .nextPort
577
578;
579; Pack into dl, baud rate starts at 0
[181]580;
[179]581 add dx,-(SerialCommand_PackedPortAndBaud_StartingPort)
582 shr dx,1
[181]583
[179]584 jmp .testFirstBaud
585
586;
587; Walk through 4 possible baud rates
[181]588;
589.nextBaud:
[179]590 inc dx
591 test dl,3
592 jz .nextPort
[181]593
594.testFirstBaud:
[179]595 call SerialCommand_IdentifyDeviceInDL_DriveInBH
596 jc .nextBaud
597
598 ret
[181]599
[179]600.exitNotFound:
[181]601 stc
[179]602 mov ah,1
603
604 ret
Note: See TracBrowser for help on using the repository browser.