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; QNICE CRC16 safeguarded data transfer tool
;
; Use case: If you do not have a RTS/CTS protected serial line on your
; hardware, then this tool ensures the data integrety via CRC16
;
; qtransfer.c contains more details
;
; done by sy2002 in May 2020
#include "../dist_kit/sysdef.asm"
#include "../dist_kit/monitor.def"
.ORG 0xFB00
MOVE STR_TITLE, R8
SYSCALL(puts, 1)
; create space on the stack
SUB BURST_WORDS, SP ; burst buffer on stack
MOVE SP, R4 ; R4 = start of burst buf.
; wait until START is received
MOVE VAR_BUFFER, R8
RSUB READ_UART, 1
MOVE STR_START, R9
SYSCALL(strcmp, 1)
CMP 0, R10
RBRA _SENDACK, Z
MOVE STR_ERR_NOSTART, R8
SYSCALL(puts, 1)
RBRA _END, 1
; send ACK
_SENDACK MOVE STR_OK, R8
SYSCALL(puts, 1)
MOVE STR_ACK, R8
RSUB WRITE_UART, 1
MOVE STR_PROGRESS, R8
SYSCALL(puts, 1)
; (<burst> x (<address><data>\n))<crc>\n
; all values are 16bit hex values where each one is
; transmitted as a 4 character ASCII string
_RX_LOOP MOVE VAR_BUFFER, R8
RSUB READ_UART, 1
; "END" ends the transmission
MOVE VAR_BUFFER, R8
MOVE STR_END, R9
SYSCALL(strcmp, 1)
CMP 0, R10
RBRA _RX_DONE, Z
; receive burst length and store it in R0
RSUB HEXSTR2I, 1
MOVE R9, R0 ; R0 = burst length
MOVE R0, R2 ; R2 = backup burst length
MOVE R4, R1 ; R1 = start of burst buf.
; receive one burst and store it at VAR_BUFFER
_RX_BURST MOVE R1, R8 ; READ_UART reads to this..
RSUB READ_UART, 1 ; ..gliding address
SUB 1, R0 ; one less element in burst
RBRA _RX_CRC, Z ; current burst done!
ADD 8, R1 ; make room for next element
RBRA _RX_BURST, 1 ; next element of burst
; receive CRC of current burst and check it
_RX_CRC MOVE CRC_BUFFER, R8
RSUB READ_UART, 1
RSUB HEXSTR2I, 1
MOVE R9, R3 ; R3 = received CRC
MOVE R2, R8 ; CRC is calculated over a..
MOVE 8, R9 ; ..buffer of size R2*8
SYSCALL(mulu, 1)
MOVE R10, R9 ; R9 = burst size * 8
MOVE R4, R8 ; R8 = start of burst buffer
RSUB CALC_CRC16, 1
CMP R10, R3 ; received CRC == calc. CRC?
RBRA _CRC_OK, Z ; yes
; CRC ERROR: Send error to UART, output error string, then end
MOVE STR_CRCERR, R8
RSUB WRITE_UART, 1
MOVE STR_ERR_CRC, R8
SYSCALL(puts, 1)
RBRA _END, 1
; "ACK" to sender
_CRC_OK MOVE STR_ACK, R8
RSUB WRITE_UART, 1
; write to memory
MOVE R2, R0 ; R0 = burst length
MOVE R4, R1 ; R1 = start of burst buffer
_WRITE_LOOP MOVE R1, R8 ; convert hex string address
RSUB HEXSTR2I, 1
MOVE R9, R5 ; R5 = target address
ADD 4, R1 ; next hex string address
MOVE R1, R8 ; convert hex string data
RSUB HEXSTR2I, 1
ADD 4, R1 ; next hex string address
MOVE R9, @R5 ; R9 = data to be written
SUB 1, R0 ; burst over?
RBRA _WRITE_LOOP, !Z ; no: continue to fill memory
RBRA _RX_LOOP, 1 ; yes: next RX iteration
_RX_DONE MOVE STR_DONE, R8
SYSCALL(puts, 1)
; show start address of transmitted program/data
MOVE STR_START_ADDR, R8
SYSCALL(puts, 1)
MOVE STR_16SPACES, R8
SYSCALL(puts, 1)
MOVE VAR_BUFFER, R8
RSUB READ_UART, 1
RSUB HEXSTR2I, 1
MOVE R9, R8
MOVE R8, R6 ; R6 = start addr. for running
SYSCALL(puthex, 1)
SYSCALL(crlf, 1)
; show overall size of transmitted program/data
MOVE STR_LENGTH, R8
SYSCALL(puts, 1)
MOVE STR_16SPACES, R8
SYSCALL(puts, 1)
MOVE VAR_BUFFER, R8
RSUB READ_UART, 1
RSUB HEXSTR2I, 1
MOVE R9, R8
SYSCALL(puthex, 1)
SYSCALL(crlf, 1)
; offer to start/run the program
MOVE STR_RUN, R8
SYSCALL(puts, 1)
SYSCALL(getc, 1)
CMP 'r', R8
RBRA _END, !Z
; run the program
SYSCALL(crlf, 1)
SYSCALL(crlf, 1)
ADD BURST_WORDS, SP ; free memory on the stack
ABRA R6, 1 ; run the program
_END ADD BURST_WORDS, SP ; free memory on the stack
SYSCALL(exit, 1)
;=============================================================================
; CRC16 Calculation and hex conversion
;=============================================================================
; Function CALC_CRC
; Input: R8 = buffer
; R9 = buffer size
; Output: R10 = 16-bit CRC
; uint16_t calc_crc(char* buffer, unsigned int size)
; {
; const uint16_t mask = 0xA001;
; uint16_t crc = 0xFFFF;
; int i = 0;
; while (i < size)
; {
; crc ^= *buffer;
; crc = (crc & 1) ? (crc >> 1) ^ mask : crc >> 1;
; buffer++;
; i++;
; }
; return crc;
; }
CALC_CRC16 INCRB
MOVE 0xFFFF, R0 ; R0 = CRC
MOVE 0xA001, R1 ; R1 = mask
MOVE R8, R2 ; R2 = buffer pointer
XOR R3, R3 ; R3 = i
_CCRC16_LOOP XOR @R2++, R0 ; crc ^= *buffer
MOVE R0, R4
AND 0xFFFB, SR ; prepare SHR: clear carry
SHR 1, R0 ; crc >> 1
AND 1, R4
RBRA _CCRC16_NOXOR, Z ; crc & 1 == 0? no mask!
XOR R1, R0 ; crc ^= mask
_CCRC16_NOXOR ADD 1, R3
CMP R3, R9
RBRA _CCRC16_LOOP, !Z
MOVE R0, R10
DECRB
RET
; Function HEXSTR2I: Interprets 4 ASCII characters as a hexadecimal value
; and converts it into a number
; Input: R8 = pointer to 4 ASCII characters
; Output: R9 = integer
HEXSTR2I INCRB
MOVE R8, R0 ; save R8
MOVE R10, R5 ; save R10
MOVE R0, R1 ; R1 iterates the input
MOVE 4, R2 ; loop counter
XOR R3, R3 ; result
_H2SI_NXT_NIB MOVE @R1++, R8 ; next character
MOVE STR_HEX_NIBBLES, R9
SYSCALL(strchr, 1)
CMP 0, R10 ; illegal character?
RBRA _HS2I_ILLEGAL, Z
SUB R9, R10 ; R10 = hex nibble: 0..15
SHL 4, R3 ; old value one nibble left
ADD R10, R3 ; add next value
SUB 1, R2 ; one less iteration
RBRA _H2SI_NXT_NIB, !Z ; iterate!
MOVE R3, R9 ; return value is in R9
RBRA _HS2I_END, 1
_HS2I_ILLEGAL XOR R9, R9
RBRA _HS2I_END, 1
_HS2I_END MOVE R0, R8
MOVE R5, R10
DECRB
RET
;=============================================================================
; UART Functions
;=============================================================================
; Function READ_UART: Reads into zero terminated buffer at R8
; Output: R9 = amount of data words read
READ_UART INCRB
MOVE R8, R3 ; save R8
XOR R1, R1 ; 0 is default return value
; read until \n
MOVE R8, R0
_RUA_NEXT_CHAR RSUB UART$GETCHAR, 1
CMP 0x000A, R8
RBRA _RUA_READ_END, Z
MOVE R8, @R0++
ADD 1, R1
RBRA _RUA_NEXT_CHAR, 1
_RUA_READ_END MOVE 0, @R0 ; add string zero terminator
_END_RUA MOVE R3, R8 ; restore R8
MOVE R1, R9 ; return number of words read
DECRB
RET
; Function WRITE_UART: send zero terminated buffer including the zero
; Input:
; R8 = Zero terminated buffer
WRITE_UART INCRB
MOVE R8, R1
MOVE R1, R0
_WUA_NEXT_CHAR MOVE @R0++, R8
RSUB UART$PUTCHAR, 1
CMP 0, @R0
RBRA _WUA_NEXT_CHAR, !Z
XOR R8, R8
RSUB UART$PUTCHAR, 1
MOVE R1, R8
DECRB
RET
; contains UART$GETCHAR and UART$PUTCHAR: we need this low level functions
; because we want to circumvent stdin/stdout and go directly to the UART
#include "../monitor/uart_library.asm"
;=============================================================================
; Constants and variables
;=============================================================================
BURST_WORDS .EQU 241 ; 8 * BURST_SIZE + 1
STR_TITLE .ASCII_W "QTransfer:\n Waiting for serial connection "
STR_OK .ASCII_W "OK!\n"
STR_PROGRESS .ASCII_W " Data transfer in progress... "
STR_DONE .ASCII_W "Done!\n"
STR_START_ADDR .ASCII_W " Start address: "
STR_LENGTH .ASCII_W " Length in words:"
STR_16SPACES .ASCII_W " "
STR_RUN .ASCII_W "Press r to run and any other key to exit"
STR_ERR_NOSTART .ASCII_P "\nError: Wrong protocol. (Are you running "
.ASCII_W "qtransfer.c on your host?)\n"
STR_ERR_CRC .ASCII_W "CRC Error!\n"
STR_START .ASCII_W "START"
STR_END .ASCII_W "END"
STR_ACK .ASCII_W "ACK"
STR_CRCERR .ASCII_W "CRCERR"
STR_HEX_NIBBLES .ASCII_W "0123456789ABCDEF"
CRC_BUFFER .BLOCK 5
VAR_BUFFER .BLOCK 9