feat(bios): BIOS interface accessible through SWI3

bbmkhash.c

@@ -25,7 +25,7 @@ int main(void) {
 ; Copyright (c) 2025 Gale Faraday\n\
 ; Licensed under MIT\n\
 \n\
-; This file generated by bbmkcmds.c\n\
+; This file generated by bbmkhash.c\n\
 \n\
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;\n\
 ;;\n\
@@ -40,10 +40,10 @@ int main(void) {
 
 	/* Command count.
 	* NOTE: This is a u16 because it gets emitted into the output assembly. */
-  	uint16_t cCmds = sizeof(s_ppszCmds) / sizeof(char *);
+	uint16_t cCmds = sizeof(s_ppszCmds) / sizeof(char *);
 
 	/* Emit command count */
-  	printf("BBCHTC\n  fdb $%.4X\n", cCmds);
+	printf("BBCHTC\n  fdb $%.4X\n", cCmds);
 
 	/* Emit table data */
 	puts("\nBBCHT");

docs/buzbee.typ

@@ -18,6 +18,10 @@ the CHIBI PC-09 hobby computer platform. It is the stock bootloader and
 interface for the PC-09. This manual goes over the usage of BUZBEE, and some of
 the technical internals of how it works and how to hack on it.
 
+BUZBEE was created primarily to debug prototype versions of the CHIBI PC-09.
+BUZBEE will grow alongside the CHIBI PC-09 project. It also functions as a
+reference implementation of an OS using the CHIBI PC-09 BIOS.
+
 The CHIBI PC-09 name and platform is copyright 2024-2025 Amber Zeller. The CHIBI
 PC-09 BIOS is copyright 2024-2025 Gale Faraday and Amber Zeller. BUZBEE is
 copyright 2025 Gale Faraday. All CHIBI PC-09 components are licensed under the
@@ -29,10 +33,11 @@ MIT license.
 
 BUZBEE is at its core a chain loader or bootloader. This means that most of the
 functionality of the CHIBI starts with using BUZBEE. BUZBEE functions are broken
-into two categories: _Internal Functions_ or "IFs," and _External Functions_ or
+into two categories: _Internal Functions_ or "IFs" defined in @if-top, and
-"EFs." IFs are native routines mapped to textual commands entered at the BUZBEE
+_External Functions_ or "EFs" in @ef-top. IFs are native routines mapped to
-prompt. EFs are native routines called through IFs. EFs can either be any user
+textual commands entered at the BUZBEE prompt. EFs are native routines called
-supplied code, or one of a set of routines in the BIOS/BUZBEE ROM or "firmware".
+through IFs. EFs can either be any user supplied code, or one of a set of
+routines in the BIOS/BUZBEE ROM or "firmware".
 
 #pagebreak()
 
@@ -44,21 +49,29 @@ listed in alphabetical order. Below in @if-table is a list of available IFs.
 
 #figure(
   table(
-    columns: (1fr, auto),
+    columns: (auto, auto, 1fr),
     inset: 10pt,
     align: center,
+    fill: (_, y) =>
+      if calc.odd(y) { luma(250) }
+      else { white },
     table.header(
-      [*Name* (pg. no.)], [*Description*]
+      [*Name* (pg. no.)], [*Command Token*], [*Description*]
     ),
     [`CALL` (#ref(<if-call>, form: "page"))],
+    [`$00`],
     [Call a resident routine in the MPU's address space.],
     [`HELP` (#ref(<if-help>, form: "page"))],
+    [`$01`],
     [Display a summary of known commands.],
     [`PEEK` (#ref(<if-peek>, form: "page"))],
+    [`$02`],
     [Dumps memory from the MPU's address space to the terminal.],
     [`POKE` (#ref(<if-poke>, form: "page"))],
+    [`$03`],
     [Overwrites memory in the MPU's address space.],
     [`SREC` (#ref(<if-srec>, form: "page"))],
+    [`$04`],
     [Switches into Motorola S-Record receive mode.],
   ),
   caption: [Table of IFs],
@@ -67,8 +80,7 @@ listed in alphabetical order. Below in @if-table is a list of available IFs.
 In the following pages these IFs are described in specific.
 
 IFs are tokenized from their textual form into a binary "bytecode" form. This
-bytecode is not reliably stable between versions, so it isn't described here in
+bytecode is described in @internals.
-specific, but a general breakdown is provided.
 
 First the text command name (eg. `CALL`) is hashed in some way into a token.
 Then conditional processing on the remainder of the line occurs. Values given in
@@ -139,17 +151,18 @@ BIOS routine.
   syntax: [`PEEK <BASE> [<HIGH>]`],
   params: (
     base: [
-      The address of the byte to dump or the base (lower bound) address of the
+      The address (two bytes) of the byte to dump or the base (lower bound)
-      byte to start dumping from if `<HIGH>` is specified.
+      address of the byte to start dumping from if `<HIGH>` is specified.
     ],
     high: [
       An optional operand given as the upper bound of the range to dump. Forms
-      a range together with `<BASE>`.
+      a range together with `<BASE>`. (two bytes)
     ],
   )
 )
 
-#lorem(120)
+Peeking memory causes the MPU to read the requested bytes and dump them to the
+screen.
 
 #pagebreak()
 
@@ -159,12 +172,13 @@ BIOS routine.
   desc: "Writes values to the MPU's address space.",
   syntax: [`POKE <ADDR> <BYTES>`],
   params: (
-    addr: "The base (low) address to start writing bytes from.",
+    addr: "The base (low) address (two bytes) to start writing bytes from.",
     bytes: "The bytes to write into memory separated by whitespace.",
   )
 )
 
-#lorem(120)
+Poking memory causes the MPU to overwrite the bytes at `<ADDR>` with the bytes
+given in `<BYTES>`.
 
 #pagebreak()
 
@@ -176,7 +190,7 @@ BIOS routine.
   params: (),
 )
 
-#lorem(120)
+Motorola S-Record mode is currently a stub.
 
 #pagebreak()
 
@@ -198,9 +212,34 @@ Some common EFs to call include the using call to reset the CHIBI PC-09 with
 = BUZBEE Reserved Memory Regions <res-mem>
 
 BUZBEE uses memory in the 0200-02FF page. A table of the layout of this memory
-is provided.
+is provided. The memory is laid out in a packed structure starting at 0200.
 
-// TODO: Provide a table of the BUZBEE memory layout.
+#table(
+  columns: (auto, 1fr, auto),
+  inset: 10pt,
+  align: center,
+  fill: (_, y) =>
+    if calc.odd(y) { luma(250) }
+    else { white },
+  table.header(
+    [*Internal Name*], [*Size (Bytes)*], [*Description*]
+  ),
+  [`input`],
+  [128],
+  [Text input buffer],
+  [`cchinput`],
+  [2],
+  [Text input buffer character count],
+  [`tokens`],
+  [64],
+  [BUZBEE token buffer],
+  [`cbtokens`],
+  [2],
+  [Count of bytes in `tokens`],
+  [`scratch`],
+  [2],
+  [Internal scratch word used for some operations],
+)
 
 #pagebreak()
 
@@ -236,4 +275,19 @@ Building the documentation can also be accomplished using `make docs`, provided
 
 = BUZBEE Internals and Modding <internals>
 
-#lorem(120)
+BUZBEE's interpreter works by "compiling" textual user commands into bytecode
+for more simply passing parameters to IFs (see @if-top). The way that works is
+the implementation dependent, but each hash is one byte (1B) in size, and
+corresponds to an IF token, which is the index of the hash.
+
+BUZBEE's source, and the surrounding BIOS source is well commented, but a
+general summary of the control flow is provided here.
+
++ BUZBEE sets up the prompt and input buffer with `NEWLINE`
++ BUZBEE enters an input processing loop that works with the CHIBI PC-09's
+  serial driver.
++ If no input is provided, restart.
++ BUZBEE makes a tokenizing pass over the input buffer.
++ BUZBEE attempts to execute the tokens, which may involve leaving the BUZBEE
+  loop, or in the event the IF returns, loops around and re-enters the BUZBEE
+  loop.

linkscript

@@ -1,9 +1,17 @@
+; BIOS
 section RESET load 8000
 section SERIAL
+
+; BIOS Interface and Utilities
+section BIOSINT load 8800
 section MEMTEST
 
+; BUZBEE Monitor
 section BUZBEE
 section BBHASHES
 
+; Static Data
 section VECTORS high 100000
 section VERSION high
+
+entry 8000

src/buzbee.s

@@ -13,15 +13,17 @@
 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-BBIN_DEPTH     EQU $7F
+BBIN_DEPTH     EQU $80 ; Input buffer depth
-BBTOKENS_DEPTH EQU $3F
+BBTOKENS_DEPTH EQU $40 ; Token buffer depth
 
   SECTION BBVARS,bss
 
 tagbbvar STRUCT
 input    rmb BBIN_DEPTH     ; Input buffer
+cchinput rmd 1              ; Input buffer char count
 tokens   rmb BBTOKENS_DEPTH ; Token buffer
-cbtokens rmb 2
+cbtokens rmd 1              ; Token buffer byte count
+scratch  rmd 1              ; Scratch word
   ENDSTRUCT
 
   ORG $0200
@@ -38,13 +40,14 @@ BBVAR tagbbvar
   EXPORT BUZBEE
 
 BUZBEE
-  bsr NEWLINE ; Setup the new input line and handle display.
+  lbsr NEWLINE       ; Setup the new input line and handle display.
-  bsr INPLOOP ; Fill input buffer.
+  bsr INPLOOP        ; Fill input buffer.
-  cmpy #$0000 ; No data?
+  cmpy #0            ; No data?
-  beq BUZBEE  ;  Try again...
+  beq BUZBEE         ;  Try again...
-  ; TODO: Parse the input buffer into tokens
+  lbsr MKINSENSITIVE ; Make the input buffer case insensitive
-  lbsr RUNIF
+  lbsr TOKENIZE      ; Try to tokenize the input buffer
-  bra BUZBEE
+  lbsr RUNIF         ; Execute token buffer, handling any errors
+  bra BUZBEE         ; Repeat
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
@@ -52,25 +55,11 @@ BUZBEE
 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Handle new lines; prints a new prompt and then clears the input buffer
-NEWLINE
-  PZSTR PROMPTLINE  ; Print prompt line
-CLRIN               ; Label to just clear input buffer without newline
-  clra              ; Init A and X
-  ldx #$0000
-NEXT@
-  sta BBVAR.input,x ; Clear input buffer
-  leax 1,x
-  cmpx #BBIN_DEPTH
-  blo NEXT@
-  ldy #$0000        ; Reset buffer fill pointer
-  rts
-
 ; Fills input buffer with characters from the serial console. Sets Y to the
 ; offset in the input buffer of the last char read.
 INPLOOP
   jsr PINCHAR          ; Try to read a char
-  cmpd #$0000          ; If no char keep waitin'
+  cmpd #0              ; If no char keep waitin'
   beq INPLOOP
   bitb #UARTF_LSR_DR   ; Is there a char in A?
   beq NOCHAR@
@@ -79,13 +68,14 @@ INPLOOP
   cmpa #$08            ; BS?
   beq HBACKSPC@        ;  Backup a char
   cmpa #$0D            ; CR?
-  beq EXIT@            ;  Then parse input buffer
+  beq HCR@             ;  Then terminate and parse input buffer
   cmpy #BBIN_DEPTH     ; Are we at the end of the input buffer?
   beq FULLBUF@         ; Handle the buffer being full
 ECHO@
   jsr POUTCHAR         ; Echo char back, this includes BS chars
   sta BBVAR.input,y    ; Add it to the input buffer
   leay 1,y
+  ; Fall through
 NOCHAR@
   ; Check for error condition, work based on The Serial Port release 19
   bitb #(UARTF_LSR_FIFO|UARTF_LSR_BI|UARTF_LSR_FE|UARTF_LSR_PE|UARTF_LSR_OE)
@@ -103,15 +93,16 @@ NOPARITY@
   PZSTR EM_FRAMING
 NOFRAM@
   bitb #UARTF_LSR_FIFO ; Check for FIFO error
-  beq INPLOOP
+  beq INPLOOP          ; Loop over
   PZSTR EM_FIFO
-  bra INPLOOP
+  bra INPLOOP          ; Loop over
-EXIT@
+HCR@
+  sty BBVAR.cchinput   ; Store buffer length
   rts
 HESC@
   lda #'^              ; Print a char that signifies that ESC was pressed
   jsr POUTCHAR
-  ldy #$0000           ; On return we cmpy #$0000 and if eq then newline.
+  ldy #0               ; On return we cmpy #0 and if eq then newline
   rts
 HBACKSPC@
   clrb                 ; Clear last char
@@ -121,7 +112,36 @@ HBACKSPC@
 FULLBUF@
   lda #$07             ; ASCII BEL
   jsr POUTCHAR
-  bra INPLOOP
+  lbra INPLOOP
+
+; Handle new lines; prints a new prompt and then clears the input buffer
+NEWLINE
+  PZSTR PROMPTLINE  ; Print prompt line
+CLRIN               ; Label to just clear input buffer without newline
+  clra              ; Init A and X
+  ldx #0
+NEXT@
+  sta BBVAR.input,x ; Clear input buffer
+  leax 1,x
+  cmpx #BBIN_DEPTH
+  blo NEXT@
+  ldy #0            ; Reset buffer fill pointer
+  rts
+
+; Makes the input buffer case insensitive
+MKINSENSITIVE
+NEXTC@
+  lda BBVAR.input,x
+  cmpa #'z            ; Is the char outside the lowercase range?
+  bhi NOTLCASE@       ;  Yes? Skip offset part
+  cmpa #'a            ; Again on the other side of the range
+  blo NOTLCASE@
+  anda #$DF           ; -32
+NOTLCASE@
+  leax 1,x            ; Ready next char
+  cmpx BBVAR.cchinput ; Are we at the end?
+  bne NEXTC@          ;  No? Loop
+  rts
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
@@ -130,7 +150,7 @@ FULLBUF@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 ; Prints a byte in A
-; @param a: byte to print
+; @param A: byte to print
 PBYTE
   pshs b
   tfr a,b      ; Transfer lower nybble into B
@@ -139,24 +159,56 @@ PBYTE
   asra
   asra
   asra
-  bsr NYB2HEX ; Print A
+  anda #$0F
+  ora #'0      ; Add '0' to offset to digits
+  cmpa #$3A    ; Hex? ':' '9'+1
+  blo SKIPA@
+  adca #6      ; Hex offset
+SKIPA@
+  jsr POUTCHAR ; Print char in A
+  andb #$0F
+  orb #'0      ; Add '0' to offset to digits
+  cmpb #$3A    ; Hex? ':' '9'+1
+  blo SKIPB@
+  adcb #6      ; Hex offset
+SKIPB@
+  tfr b,a      ; Print char in B
   jsr POUTCHAR
-  tfr b,a      ; Print B next
+  puls b       ; Restore B
-  bsr NYB2HEX ; Print B
-  jsr POUTCHAR
-  puls b
   rts
 
-; Converts a nybble into a valid hex digit
+; Converts a hexadecimal sequence into a byte value
-; @param a: nybble to convert to a char
+; @param D: hex representation of a byte with A: MSD B: LSD
-; @return a: resulting char
+; @return A: returned byte value
-NYB2HEX
+; NOTE: Conversion logic credit to Wozniak. This code unrolled for speed.
-  anda #$0F
+HEX2BYT
-  ora #'0     ; Add "0"
+  eora #$B0         ; Map digits to 0-9
-  cmpa #$3A   ; ":" "9"+1
+  cmpa #9+1         ; Is it a decimal?
-  bcc SKIP@
+  blo AISDEC@       ;  Yes? skip hex adjust
-  adca #6     ; Add offset to "A" in ascii
+  adca #$88         ; Map 'A'-'F' to $FA-$FF
-SKIP@
+  cmpa #$FA         ; Hex char?
+  blo BADHEX@       ;  No? Print error
+AISDEC@
+  asla              ; Shift MSD into upper nybble of A
+  asla
+  asla
+  asla
+; Do B part
+  eorb #$B0         ; Map digits to 0-9
+  cmpa #9+1         ; Is it a decimal?
+  blo BISDEC@       ; Yes? skip hex adjust
+  adcb #$88         ; Map 'A'-'F' to $FA-$FF
+  andb #$0F         ; Mask high nybble
+  cmpb #$0A         ; Hex char?
+  blo BADHEX@       ;  No? Print error
+BISDEC@
+  stb BBVAR.scratch ; Store low nybble in scratch buffer
+  ora BBVAR.scratch ; Combine the nybbles
+  rts
+BADHEX@
+  PZSTR EM_BADHEX   ; Print an error message
+  clrd              ; Prevent RUNIF from executing
+  std BBVAR.cbtokens
   rts
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -165,19 +217,89 @@ SKIP@
 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Makes a hash of four chars in BBIN starting at offset X.
+; Attempts to parse the input buffer into tokens depending on the command
-; @param X: offset in BBIN to read the four chars from
+TOKENIZE
+  ldd BBVAR.cchinput   ; Do we have input to work with?
+  cmpd #4              ; Do we have even enough space for a string command
+  blo TOKFAIL@         ;  No? GTFO
+  ldy #0               ; Initialize Y; used to track current position in BBVAR.input
+  ldx #0               ; Initialize X; used to track position in BBVAR.tokens
+  bsr SKIPTONEXTC      ; Get the next non-whitespace char
+  bsr MKCMDSUM         ; Hash the first four non-whitespace chars
+  bsr HASH2TOKEN       ; Try to turn that hash into a proper token
+  bcs TOKFAIL@
+  bra STTOK@           ; Store token
+NEXTHEX@               ; Next hex token
+  bsr SKIPTONEXTC      ; Skip to next whitespace
+  ldd BBVAR.input,y    ; Get hex value (two digits)
+  bsr HEX2BYT          ; Convert hex value to byte value
+STTOK@
+  sta BBVAR.tokens,x   ; Store curent token
+  leax 1,x             ; Advance to next token
+  cmpx #BBTOKENS_DEPTH ; Is this next token in bounds?
+  beq FULLBUF@         ;  No? handle a full buffer
+  bra NEXTHEX@         ; Try to turn the next character into a hex value
+FULLBUF@
+  PZSTR EM_FULLTOKBUF  ; Print an error message
+  clrd                 ; Say we wrote no tokens
+  std BBVAR.cbtokens
+  rts
+TOKFAIL@
+  PZSTR EM_TOKFAIL     ; Print tokenization fail
+  clrd                 ; Say we wrote no tokens
+  std BBVAR.cbtokens
+  rts
+
+; Converts a runtime command hash into a portable token. Command tokens are
+; indexes into BBCHT, which is generated at compile-time
+; @param A: runtime hash
+; @return A: output token
+; @return CC.C: set if error state, cleared otherwise
+HASH2TOKEN
+  pshs x           ; Preserve & init X; other routines in this group use it
+  ldx #0
+NEXTHASH@
+  cmpa BBCHT,x     ; Is this hash our hash?
+  beq THISHASH@    ;  Yes? turn it into a token
+  leax 1,x         ; Begin considering next hash
+  cmpx BBCHTC      ; Is the next hash even in the table?
+  blo NEXTHASH@    ;  Yes? try this next hash, No? fall through
+  PZSTR EM_BADHASH CALL; Print an error message to the user
+  puls x
+  orcc #1          ; Set CC.C to indicate error
+  rts
+THISHASH@
+  puls x
+  andcc #$FE       ; Clear CC.C to indicate success
+  rts
+
+; Makes a hash of four chars in BBIN starting at offset X
+; @param Y: offset in BBIN to read the four chars from
 ; @return A: resulting hash
+; @return Y: offset after hash processing
 MKCMDSUM
   pshs b
   ldb #4             ; Loop over four chars
   clra               ; Initialize accumulator
 NEXTC@
-  suba BBVAR.input,x ; Subtract current char from accumulator
+  suba BBVAR.input,y ; Subtract current char from accumulator
-  leax 1,x           ; Next char
+  leax 1,y           ; Next char
   decb               ; Reduce count
   cmpb #0            ; Are we at the end?
   bne NEXTC@         ;  No? loop
+  puls b
+  rts
+
+; Skips "whitespace" to the next semantic char
+; @param Y: current index in text buffer
+; @return Y: resulting index in text buffer
+SKIPTONEXTC
+  lda BBVAR.input,y ; Get our char?
+  cmpa #$20         ; SPACE or control char?
+  bhi EXIT@         ;  Yes? End
+  leay 1,y          ; Iterate next char
+  bra SKIPTONEXTC
+EXIT@
   rts
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -190,24 +312,21 @@ NEXTC@
 ; @corrupts B
 ; @return X: command data table index
 RUNIF
+  clrd             ; Do we have any tokens?
+  cmpd BBVAR.cbtokens
+  beq NOTOK@
   ldx #0           ; Counting up from zero
   lda BBVAR.tokens ; Load token
-NEXTHASH@
+  tfr a,d          ; Get the index in D
-  cmpa BBCHT,x     ; Is this hash our hash?
+  clra
-  beq CALCPTR@     ;  Yes? skip to next step to put ptr in x
-  leax 1,x         ; Begin considering next hash
-  cmpx BBCHTC      ; Is this the last byte?
-  blo NEXTHASH@    ;  No? try next hash, Yes? fall through
-  PZSTR EM_BADCMD  ; Print an error message
-  lbra IFHELP      ; Proceed to call "HELP"
-CALCPTR@
-  tfr x,d          ; Swap into d to do a cheap multiply
   asld             ; Cheaply << to get *2, pointer size
-  tfr d,x          ; Restore x from d and jump to function at index
+  tfr d,x          ; Move to X so we can use indexed mode with the offset
-  jmp [BBCMDPTRTBL,x]
+  jmp [IFPTRTBL,x] ; Select IF
+NOTOK@
+  rts
 
 ; IF pointer table
-BBCMDPTRTBL
+IFPTRTBL
   fdb IFCALL
   fdb IFHELP
   fdb IFPEEK
@@ -238,40 +357,25 @@ IFPEEK
   ldd BBVAR.cbtokens   ; One 16-bit token given, single peek
   cmpd #3
   lblo INVALIDARG      ; Not enough args given
-  bhi SELFORBAC@       ; Select forward or backward peek
+  bhi SELTYPE@         ; Select forward or backward peek
 SINGLE@
   lda [BBVAR.tokens+1] ; Get byte
   lbsr PBYTE           ; Print peek byte
   rts
-SELFORBAC@
+SELTYPE@
   ldd BBVAR.cbtokens   ; Have enough tokens?
   cmpd #5
   lbne INVALIDARG      ;  No? bounce out
   ldd BBVAR.tokens+1   ; Are we forwards (BASE < HIGH)?
   cmpd BBVAR.tokens+3
   beq SINGLE@          ; Gracefully handle BASE == HIGH
-  blo PEEKFWD
+  bhi INVALIDARG       ; Malformed if BASE > HIGH
-  bhi PEEKBACK
-
-; Peek forward
-PEEKFWD
-  ldx BBVAR.tokens+1  ; Get BASE
-NEXT@
-  lda ,x+             ; Get the next byte
-  lbsr PBYTE          ; Print our byte
-  cmpx BBVAR.tokens+3 ; Are we at <HIGH> yet?
-  bne NEXT@           ;  No? loop
-  rts
-
-; Peek backwards
-PEEKBACK
   ldx BBVAR.tokens+1   ; Get BASE
-PREV@
+NEXT@
-  lda 0,x              ; Get current byte
+  lda ,x+              ; Get the next byte
-  leax -1,x            ; Prep for next byte
   lbsr PBYTE           ; Print our byte
   cmpx BBVAR.tokens+3  ; Are we at <HIGH> yet?
-  bne PREV@            ;  No? loop
+  bne NEXT@            ;  No? loop
   rts
 
 ; Poke bytes into memory
@@ -297,12 +401,12 @@ IFSREC
 
 ; Invalid argument IF tail
 INVALIDARG
-  PZSTR EM_MISSINGARG
+  PZSTR EM_BADARG
   rts
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
-;; BUZBEE Strings and Tables
+;; BUZBEE Strings and Fixed Data
 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -327,20 +431,29 @@ PROMPTLINE
   fcb $0D,$0A,$25,$00 ; CR LF '%' NUL
 
 EM_OVERRUN
-  fcc "!!! Overrun Error !!!"
+  fcc "!!! UART Overrun Error !!!"
   fcb $0D,$0A,$00
 EM_PARITY
-  fcc "!!! Parity Error !!!"
+  fcc "!!! UART Parity Error !!!"
   fcb $0D,$0A,$00
 EM_FRAMING
-  fcc "!!! Framing Error !!!"
+  fcc "!!! UART Framing Error !!!"
   fcb $0D,$0A,$00
 EM_FIFO
-  fcc "!!! FIFO Error !!!"
+  fcc "!!! UART FIFO Error !!!"
   fcb $0D,$0A,$00
-EM_BADCMD
+EM_BADHASH
   fcc "!!! Bad Command Hash !!!"
   fcb $0D,$0A,$00
-EM_MISSINGARG
+EM_BADARG
-  fcc "!!! Missing Arguments !!!"
+  fcc "!!! Malformed Arguments !!!"
+  fcb $0D,$0A,$00
+EM_TOKFAIL
+  fcc "!!! Tokenization Failure !!!"
+  fcb $0D,$0A,$00
+EM_BADHEX
+  fcc "!!! Malformed Hex Value !!!"
+  fcb $0D,$0A,$00
+EM_FULLTOKBUF
+  fcc "!!! Token Buffer Overrun !!!"
   fcb $0D,$0A,$00

src/memtest.s

@@ -1,44 +0,0 @@
-; CHIBI PC-09 Prototype #1 Boot ROM -- Memory Testing Routines
-; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
-; Licensed under MIT
-
-  INCLUDE "hardware.inc"
-  INCLUDE "serial.inc"
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;; Memory Testing Routines
-;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-  SECTION MEMTEST
-
-  EXPORT RAMTEST
-
-; RAM testing routine. Ported to 6809 from 6800, based on source for ROBIT-2 for
-; MIKBUG.
-RAMTEST
-  ldx #STACK_TOP+1     ; bottom of testable SRAM, $0200
-AGAIN@                 ; Store 1 in memory
-  lda #1               ; Set [X] to 1
-  sta 0,x
-  cmpa 0,x             ; If failed print out an error indicator
-  bne ERR@
-NEXT@                  ; Loop point for next address
-  asla                 ; Shift A and [X] left
-  asl 0,x
-  cmpa 0,x             ; Compare A and [X]
-  bne ERR@
-  cmpa #$80            ; Only test up to $80
-  bne NEXT@            ; Loop if not $80
-  cmpx #$60FF          ; Compare X to end of RAM
-  beq PASS@            ; Finish if we're at the end
-  leax 1,x             ; Increment X
-  bra AGAIN@
-ERR@                   ; Write out error indicator
-  ldb #'X
-  jsr POUTCHAR
-PASS@                  ; Pass test
-  ldb #'P
-  jsr POUTCHAR
-  rts

src/reset.s

@@ -4,7 +4,6 @@
 
   INCLUDE "buzbee.inc"
   INCLUDE "hardware.inc"
-  INCLUDE "memtest.inc"
   INCLUDE "serial.inc"
   INCLUDE "version.inc"
 
@@ -24,7 +23,7 @@ RESET
 CLRSTACK
   ; Initialize the system stack
   clra               ; Init A & X to zero out the stack
-  ldx #$0000
+  ldx #0
 NEXT@
   sta STACK_BOTTOM,x ; Write a zero and progress to the next byte
   leax 1,x
@@ -36,18 +35,12 @@ BOOTSCR
   lda #13      ; 9600 baud
   ldb #%11     ; 8N1
   jsr INITUART ; Initialize serial console
-  ldx #VERMSG  ; Print version information
+  PZSTR VERMSG ; Print version information
-  jsr POUTZSTR
-
-; Progress to POST
-POST
-  jsr RAMTEST
 
 ; Hand off control to the BUZBEE monitor and print notification of leaving the
 ; firmware
 ENTERMON
-  ldx #TXTRUN
+  PZSTR TXTRUN
-  jsr POUTZSTR
   jmp BUZBEE
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -57,4 +50,5 @@ ENTERMON
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 TXTRUN
-  fcn "<3RUN<3"
+  fcc "<3RUN<3"
+  fcb $0D,$0A,$00

src/utils.inc

@@ -1,7 +1,8 @@
-; CHIBI PC-09 Prototype #1 -- Memory Testing Routines Header
+; CHIBI PC-09 Prototype #1 -- BIOS Utilities Header
 ; Copyright (c) 2025 Amber Zeller, Gale Faraday
 ; Licensed under MIT
 
 ; vim: ft=asm
 
-RAMTEST IMPORT
+ROBIT IMPORT
+PRINTVER IMPORT

src/utils.s

@@ -0,0 +1,99 @@
+; CHIBI PC-09 Prototype #1 Boot ROM -- BIOS Utilities
+; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
+; Licensed under MIT
+
+  INCLUDE "hardware.inc"
+  INCLUDE "serial.inc"
+  INCLUDE "version.inc"
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; CHIBI/O Stable BIOS Interface
+;;
+;; Called through SWI3
+;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+  SECTION BIOSINT
+
+  EXPORT CHIBIO
+
+; CHIBI/O Entrypoint -- Stable, but defined by linkerscript $8800
+; @param A: Function ID
+CHIBIO
+  tfr a,d              ; 8-to-16 tfr, fill both a and b
+  clra                 ; Clear MSB
+  asld                 ; Convert to word offset
+  tfr d,x              ; Put in X for indexing mode
+  jmp [CHIBIOPTRTBL,x] ; Jump!
+
+; Jump table TODO: Document function IDs and pointers
+CHIBIOPTRTBL
+  fdb IOPRINTVER ; Print the firmware version string
+  fdb $0000      ; TODO: Interactive BIOS setup utilitiy call
+  fdb ROBIT      ; Access the ROBIT memory test
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; CHIBI/O Function Implementations
+;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+; Prints the firmware's version information
+IOPRINTVER
+  PZSTR VERMSG
+  rti
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; Memory Testing Routines
+;;
+;; This family of BIOS routines does not return, upon completion the CHIBI must
+;; be reset.
+;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+  SECTION MEMTEST
+
+  EXPORT ROBIT
+
+; RAM testing routine. Ported to 6809 from 6800, based on source for ROBIT-2 for
+; MIKBUG.
+ROBIT
+  ldx #STACK_TOP+1     ; bottom of testable SRAM, $0200
+AGAIN@                 ; Store 1 in memory
+  lda #1               ; Set [X] to 1
+  sta 0,x
+  cmpa 0,x             ; If failed print out an error indicator
+  bne ERR@
+NEXT@                  ; Loop point for next address
+  asla                 ; Shift A and [X] left
+  asl 0,x
+  cmpa 0,x             ; Compare A and [X]
+  bne ERR@
+  cmpa #$80            ; Only test up to $80
+  bne NEXT@            ; Loop if not $80
+  cmpx #$60FF          ; Compare X to end of RAM
+  beq PASS@            ; Finish if we're at the end
+  leax 1,x             ; Increment X
+  bra AGAIN@
+ERR@                   ; Write out error indicator
+  ldb #'X
+  jsr POUTCHAR
+PASS@                  ; Pass test
+  ldb #'P
+  jsr POUTCHAR
+  bra HALT
+
+; Prints a message about completing a memory test prompting the user to reset
+; then puts the MPU in a loop where it only responds to interrupts, effectively
+; halting the CHIBI
+HALT
+  PZSTR MSG_FINISH
+LOOP@
+  sync
+  bra LOOP@
+
+MSG_FINISH
+  fcc "Memory test finished! Please reset"
+  fcb $0D,$0A,$00

src/vecs.s

@@ -3,6 +3,7 @@
 ; Licensed under MIT
 
   INCLUDE "reset.inc"
+  INCLUDE "utils.inc"
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
@@ -13,11 +14,11 @@
   SECTION VECTORS
 
 VECTORS
-  fdb $0000 ; Exception
+  fdb $0000  ; Exception
-  fdb $0000 ; SWI3
+  fdb CHIBIO ; SWI3
-  fdb $0000 ; SWI2
+  fdb $0000  ; SWI2
-  fdb $0000 ; FIRQ
+  fdb $0000  ; FIRQ
-  fdb $0000 ; IRQ
+  fdb $0000  ; IRQ
-  fdb $0000 ; SWI
+  fdb $0000  ; SWI
-  fdb $0000 ; NMI
+  fdb $0000  ; NMI
-  fdb RESET ; Reset
+  fdb RESET  ; Reset