feat(buzbee): hexadecimal to byte conversion routine and skip-whitespace routine for tokenizer
This commit is contained in:
170
src/buzbee.s
170
src/buzbee.s
@@ -13,15 +13,17 @@
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;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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BBIN_DEPTH EQU $7F
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BBTOKENS_DEPTH EQU $3F
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BBIN_DEPTH EQU $80 ; Input buffer depth
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BBTOKENS_DEPTH EQU $40 ; Token buffer depth
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SECTION BBVARS,bss
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tagbbvar STRUCT
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input rmb BBIN_DEPTH ; Input buffer
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cchinput rmd 1 ; Input buffer char count
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tokens rmb BBTOKENS_DEPTH ; Token buffer
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cbtokens rmb 2
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cbtokens rmd 1 ; Token buffer byte count
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scratch rmd 1 ; Scratch word
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ENDSTRUCT
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ORG $0200
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@@ -38,10 +40,10 @@ BBVAR tagbbvar
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EXPORT BUZBEE
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BUZBEE
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bsr NEWLINE ; Setup the new input line and handle display.
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bsr INPLOOP ; Fill input buffer.
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cmpy #$0000 ; No data?
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beq BUZBEE ; Try again...
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lbsr NEWLINE ; Setup the new input line and handle display.
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bsr INPLOOP ; Fill input buffer.
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cmpy #$0000 ; No data?
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beq BUZBEE ; Try again...
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; TODO: Parse the input buffer into tokens
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lbsr RUNIF
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bra BUZBEE
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@@ -52,20 +54,6 @@ BUZBEE
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;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Handle new lines; prints a new prompt and then clears the input buffer
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NEWLINE
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PZSTR PROMPTLINE ; Print prompt line
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CLRIN ; Label to just clear input buffer without newline
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clra ; Init A and X
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ldx #$0000
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NEXT@
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sta BBVAR.input,x ; Clear input buffer
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leax 1,x
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cmpx #BBIN_DEPTH
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blo NEXT@
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ldy #$0000 ; Reset buffer fill pointer
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rts
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; Fills input buffer with characters from the serial console. Sets Y to the
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; offset in the input buffer of the last char read.
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INPLOOP
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@@ -79,13 +67,14 @@ INPLOOP
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cmpa #$08 ; BS?
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beq HBACKSPC@ ; Backup a char
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cmpa #$0D ; CR?
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beq EXIT@ ; Then parse input buffer
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beq HCR@ ; Then terminate and parse input buffer
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cmpy #BBIN_DEPTH ; Are we at the end of the input buffer?
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beq FULLBUF@ ; Handle the buffer being full
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ECHO@
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jsr POUTCHAR ; Echo char back, this includes BS chars
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sta BBVAR.input,y ; Add it to the input buffer
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leay 1,y
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; Fall through
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NOCHAR@
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; Check for error condition, work based on The Serial Port release 19
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bitb #(UARTF_LSR_FIFO|UARTF_LSR_BI|UARTF_LSR_FE|UARTF_LSR_PE|UARTF_LSR_OE)
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@@ -103,10 +92,11 @@ NOPARITY@
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PZSTR EM_FRAMING
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NOFRAM@
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bitb #UARTF_LSR_FIFO ; Check for FIFO error
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beq INPLOOP
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beq INPLOOP ; Loop over
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PZSTR EM_FIFO
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bra INPLOOP
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EXIT@
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bra INPLOOP ; Loop over
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HCR@
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sty BBVAR.cchinput ; Store buffer length
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rts
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HESC@
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lda #'^ ; Print a char that signifies that ESC was pressed
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@@ -121,7 +111,21 @@ HBACKSPC@
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FULLBUF@
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lda #$07 ; ASCII BEL
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jsr POUTCHAR
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bra INPLOOP
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lbra INPLOOP
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; Handle new lines; prints a new prompt and then clears the input buffer
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NEWLINE
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PZSTR PROMPTLINE ; Print prompt line
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CLRIN ; Label to just clear input buffer without newline
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clra ; Init A and X
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ldx #$0000
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NEXT@
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sta BBVAR.input,x ; Clear input buffer
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leax 1,x
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cmpx #BBIN_DEPTH
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blo NEXT@
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ldy #$0000 ; Reset buffer fill pointer
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rts
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;
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@@ -130,7 +134,7 @@ FULLBUF@
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Prints a byte in A
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; @param a: byte to print
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; @param A: byte to print
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PBYTE
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pshs b
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tfr a,b ; Transfer lower nybble into B
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@@ -148,24 +152,58 @@ PBYTE
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rts
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; Converts a nybble into a valid hex digit
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; @param a: nybble to convert to a char
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; @return a: resulting char
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; @param A: nybble to convert to a char
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; @return A: resulting char
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NYB2HEX
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anda #$0F
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ora #'0 ; Add "0"
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cmpa #$3A ; ":" "9"+1
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bcc SKIP@
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blo SKIP@
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adca #6 ; Add offset to "A" in ascii
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SKIP@
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rts
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; Converts a hexadecimal sequence into a byte value
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; @param D: hex representation of a byte with A: MSD B: LSD
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; @return A: returned byte value
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; NOTE: Conversion logic credit to Wozniak. This code unrolled for speed.
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HEX2BYT
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eora #$B0 ; Map digits to 0-9
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cmpa #9+1 ; Is it a decimal?
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blo AISDEC@ ; Yes? skip hex adjust
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adca #$88 ; Map 'A'-'F' to $FA-$FF
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cmpa #$FA ; Hex char?
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blo BADHEX@ ; No? Print error
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AISDEC@
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asla ; Shift MSD into upper nybble of A
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asla
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asla
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asla
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; Do B part
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eorb #$B0 ; Map digits to 0-9
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cmpa #9+1 ; Is it a decimal?
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blo BISDEC@ ; Yes? skip hex adjust
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adcb #$88 ; Map 'A'-'F' to $FA-$FF
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andb #$0F ; Mask high nybble
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cmpb #$0A ; Hex char?
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blo BADHEX@ ; No? Print error
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BISDEC@
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stb BBVAR.scratch ; Store low nybble in scratch buffer
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ora BBVAR.scratch ; Combine the nybbles
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rts
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BADHEX@
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PZSTR EM_BADHEX ; Print an error message
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clrd ; Prevent RUNIF from executing
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std BBVAR.cbtokens
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rts
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;
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;; BUZBEE Tokenizing Routines
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;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Makes a hash of four chars in BBIN starting at offset X.
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; Makes a hash of four chars in BBIN starting at offset X
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; @param X: offset in BBIN to read the four chars from
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; @return A: resulting hash
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MKCMDSUM
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@@ -180,6 +218,18 @@ NEXTC@
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bne NEXTC@ ; No? loop
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rts
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; Skips "whitespace" to the next semantic char
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; @param Y: current index in text buffer
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; @return Y: resulting index in text buffer
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SKIPTONEXTC
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lda BBVAR.input,y ; Get our char?
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cmpa #$20 ; SPACE or control char?
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bhi EXIT@ ; Yes? End
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leay 1,y ; Iterate next char
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bra SKIPTONEXTC
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EXIT@
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rts
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;
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;; BUZBEE IF Handling Functions
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@@ -190,6 +240,9 @@ NEXTC@
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; @corrupts B
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; @return X: command data table index
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RUNIF
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clrd ; Do we have any tokens?
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cmpd BBVAR.cbtokens
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beq NOTOK@
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ldx #0 ; Counting up from zero
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lda BBVAR.tokens ; Load token
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NEXTHASH@
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@@ -198,13 +251,15 @@ NEXTHASH@
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leax 1,x ; Begin considering next hash
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cmpx BBCHTC ; Is this the last byte?
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blo NEXTHASH@ ; No? try next hash, Yes? fall through
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PZSTR EM_BADCMD ; Print an error message
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PZSTR EM_BADHASH ; Print an error message
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lbra IFHELP ; Proceed to call "HELP"
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CALCPTR@
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tfr x,d ; Swap into d to do a cheap multiply
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asld ; Cheaply << to get *2, pointer size
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tfr d,x ; Restore x from d and jump to function at index
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jmp [BBCMDPTRTBL,x]
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NOTOK@
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rts
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; IF pointer table
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BBCMDPTRTBL
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@@ -238,40 +293,25 @@ IFPEEK
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ldd BBVAR.cbtokens ; One 16-bit token given, single peek
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cmpd #3
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lblo INVALIDARG ; Not enough args given
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bhi SELFORBAC@ ; Select forward or backward peek
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bhi SELTYPE@ ; Select forward or backward peek
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SINGLE@
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lda [BBVAR.tokens+1] ; Get byte
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lbsr PBYTE ; Print peek byte
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rts
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SELFORBAC@
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SELTYPE@
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ldd BBVAR.cbtokens ; Have enough tokens?
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cmpd #5
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lbne INVALIDARG ; No? bounce out
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ldd BBVAR.tokens+1 ; Are we forwards (BASE < HIGH)?
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cmpd BBVAR.tokens+3
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beq SINGLE@ ; Gracefully handle BASE == HIGH
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blo PEEKFWD
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bhi PEEKBACK
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; Peek forward
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PEEKFWD
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ldx BBVAR.tokens+1 ; Get BASE
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NEXT@
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lda ,x+ ; Get the next byte
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lbsr PBYTE ; Print our byte
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cmpx BBVAR.tokens+3 ; Are we at <HIGH> yet?
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bne NEXT@ ; No? loop
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rts
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; Peek backwards
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PEEKBACK
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bhi INVALIDARG ; Malformed if BASE > HIGH
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ldx BBVAR.tokens+1 ; Get BASE
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PREV@
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lda 0,x ; Get current byte
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leax -1,x ; Prep for next byte
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NEXT@
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lda ,x+ ; Get the next byte
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lbsr PBYTE ; Print our byte
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cmpx BBVAR.tokens+3 ; Are we at <HIGH> yet?
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bne PREV@ ; No? loop
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bne NEXT@ ; No? loop
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rts
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; Poke bytes into memory
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@@ -297,12 +337,12 @@ IFSREC
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; Invalid argument IF tail
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INVALIDARG
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PZSTR EM_MISSINGARG
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PZSTR EM_BADARG
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rts
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;
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;; BUZBEE Strings and Tables
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;; BUZBEE Strings and Fixed Data
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;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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@@ -327,20 +367,26 @@ PROMPTLINE
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fcb $0D,$0A,$25,$00 ; CR LF '%' NUL
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EM_OVERRUN
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fcc "!!! Overrun Error !!!"
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fcc "!!! UART Overrun Error !!!"
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fcb $0D,$0A,$00
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EM_PARITY
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fcc "!!! Parity Error !!!"
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fcc "!!! UART Parity Error !!!"
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fcb $0D,$0A,$00
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EM_FRAMING
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fcc "!!! Framing Error !!!"
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fcc "!!! UART Framing Error !!!"
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fcb $0D,$0A,$00
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EM_FIFO
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fcc "!!! FIFO Error !!!"
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fcc "!!! UART FIFO Error !!!"
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fcb $0D,$0A,$00
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EM_BADCMD
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EM_BADHASH
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fcc "!!! Bad Command Hash !!!"
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fcb $0D,$0A,$00
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EM_MISSINGARG
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fcc "!!! Missing Arguments !!!"
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EM_BADARG
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fcc "!!! Malformed Arguments !!!"
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fcb $0D,$0A,$00
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EM_TOKFAIL
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fcc "!!! Tokenization Failure !!!"
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fcb $0D,$0A,$00
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EM_BADHEX
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fcc "!!! Maleformed Hex Value !!!"
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fcb $0D,$0A,$00
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