fix(chibio): added missing header

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\

docs/firmware.typ

@@ -1,26 +1,22 @@
 #set document(
-  title: "BUZBEE Manual",
+  title: "CHIBI PC-09 Firmware Manual",
   author: "Gale Faraday",
-  description: "CHIBI PC-09 machine language monitor BUZBEE technical and user manual",
+  description: "CHIBI PC-09 Firmware: BIOS, CHIBIO, and BUZBEE documentation",
 )
 
 #import "style.typ": conf
 #show: conf.with(
-  title: [BUZBEE User Manual and Technical Reference],
-  subtitle: [A CHIBI PC-09 Machine Language Monitor],
+  title: [CHIBI PC-09 Firmware Manual and Technical Reference],
+  subtitle: [A Complete Firmware Package for the CHIBI PC-09],
   author: [Gale Faraday],
 )
 
 = Introduction <intro>
 
-BUZBEE is a "machine language monitor" styled after Steve Wozniak's WOZMON for
-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.
+This is the complete, stock firmware package for Amber Zeller's CHIBI PC-09
+hobby computer. Featuring Gale Faraday's BUZBEE machine language monitor
+(@bb-intro), the CHIBI/O BIOS interface (@chibio-intro), and several inbuilt
+programs (@programs).
 
 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
@@ -29,220 +25,6 @@ MIT license.
 
 #pagebreak()
 
-= BUZBEE Functions <bbfunc>
-
-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" defined in @if-top, and
-_External Functions_ or "EFs" in @ef-top. IFs are native routines mapped to
-textual commands entered at the BUZBEE prompt. EFs are native routines called
-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()
-
-== Internal Functions (IFs) <if-top>
-
-Internal Functions are the textual commands that BUZBEE interprets from the
-command line to execute the user's wish. Internal Functions are canonically
-listed in alphabetical order. Below in @if-table is a list of available IFs.
-
-#figure(
-  table(
-    columns: (auto, auto, 1fr),
-    inset: 10pt,
-    align: center,
-    fill: (_, y) =>
-      if calc.odd(y) { luma(250) }
-      else { white },
-    table.header(
-      [*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],
-) <if-table>
-
-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 described in @internals.
-
-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
-hex are encoded as their corresponding bytes directly. The token buffer
-mechanics are described more in @internals. Subcommands are also hashed into
-tokens.
-
-#pagebreak()
-
-// Function for creating IF page headers
-#let _ifpagehead(
-  desc: none,
-  syntax: none,
-  params: (),
-) = {
-  smallcaps[#desc]
-  parbreak()
-  [Syntax: #syntax]
-  parbreak()
-  [Parameters: ]
-  if params.len() > 0 {
-    for (param, desc) in params [
-      - #raw("<" + upper(param) + ">"): #desc
-    ]
-  } else {
-    text(style: "italic")[N/A]
-  }
-}
-
-=== IF: `CALL` <if-call>
-
-#_ifpagehead(
-  desc: "Calls a resident routine in the MPU's address space.",
-  syntax: [`CALL <PTR>`],
-  params: (
-    ptr: "An absolute pointer to a position in the 6309 MPU's memory map.",
-  ),
-)
-
-Call takes an absolute pointer into the MPU's address space to call as if it
-were a subroutine using `JSR`.
-
-// TODO: For when CHIBI PC-09 Prototype #2 comes out or whenever we get banking
-// add it here "Special care must be taken to properly bank in the correct
-// memory banks before executing this command." yadda yadda
-
-#pagebreak()
-
-=== IF: `HELP` <if-help>
-
-#_ifpagehead(
-  desc: "Displays a summary of available IFs.",
-  syntax: [`HELP`],
-  params: ()
-)
-
-`HELP` does what it says on the tin. It should be noted that between Git tags of
-the firmware the message displayed by this may be incomplete or innaccurate.
-Internally all this does is print a string with the UART using the `POUTZSTR`
-BIOS routine.
-
-#pagebreak()
-
-=== IF: `PEEK` <if-peek>
-
-#_ifpagehead(
-  desc: "Dumps memory from the MPU's address space to the terminal.",
-  syntax: [`PEEK <BASE> [<HIGH>]`],
-  params: (
-    base: [
-      The address (two bytes) of the byte to dump or the base (lower bound)
-      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>`. (two bytes)
-    ],
-  )
-)
-
-Peeking memory causes the MPU to read the requested bytes and dump them to the
-screen.
-
-#pagebreak()
-
-=== IF: `POKE` <if-poke>
-
-#_ifpagehead(
-  desc: "Writes values to the MPU's address space.",
-  syntax: [`POKE <ADDR> <BYTES>`],
-  params: (
-    addr: "The base (low) address (two bytes) to start writing bytes from.",
-    bytes: "The bytes to write into memory separated by whitespace.",
-  )
-)
-
-Poking memory causes the MPU to overwrite the bytes at `<ADDR>` with the bytes
-given in `<BYTES>`.
-
-#pagebreak()
-
-=== IF: `SREC` <if-srec>
-
-#_ifpagehead(
-  desc: "Switches into Motorola S-Record receive mode.",
-  syntax: [`SREC`],
-  params: (),
-)
-
-Motorola S-Record mode is currently a stub.
-
-#pagebreak()
-
-== External Functions (EFs) <ef-top>
-
-External functions are any native user code that can be called with `CALL` (see
-@if-call). This mechanism is usable to run any code or routine in memory as
-though interactively using the MPU's `JSR` instruction.
-
-=== EFs in ROM <ef-rom>
-
-Some common EFs to call include the using call to reset the CHIBI PC-09 with
-`CALL 8000`.
-
-// TODO: Talk about memory test and BIOS interface
-
-#pagebreak()
-
-= BUZBEE Reserved Memory Regions <res-mem>
-
-BUZBEE uses memory in the 0200-02FF page. A table of the layout of this memory
-is provided. The memory is laid out in a packed structure starting at 0200.
-
-#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()
-
 = Building CHIBI PC-09 Firmware from Source <building>
 
 Building the CHIBI PC-09 firmware from source requires LWTOOLS
@@ -273,10 +55,242 @@ Building the documentation can also be accomplished using `make docs`, provided
 
 #pagebreak()
 
-= BUZBEE Internals and Modding <internals>
+= Programs in ROM <programs>
+
+Some simple programs are included in the CHIBI PC-09's firmware ROM and can be
+called through BUZBEE's `CALL` command. Soft reseting the CHIBI PC-09 is also
+handled through this interface by calling `$8000` or the ROM entrypoint.
+
+A simple memory test based on ROBIT-2 for the SWTPC is included at `$9000`.
+
+#pagebreak()
+
+= CHIBI/O BIOS Interface <chibio-intro>
+
+#lorem(120)
+
+#pagebreak()
+
+= BUZBEE Machine Language Monitor <bb-intro>
+
+BUZBEE is a "machine language monitor" styled after Steve Wozniak's WOZMON for
+the CHIBI PC-09 computer platform. It is the stock bootloader and
+interface for the PC-09. This chapter goes over the usage of BUZBEE, and some of
+the technical internals of how it works and how to use 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.
+
+#pagebreak()
+
+== BUZBEE Functions <bbfunc>
+
+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 called
+_Internal Functions_ or "IFs". These are documented in @bbif-top. BUZBEE
+functions are native functions mapped to textual commands entered at the BUZBEE
+prompt.
+
+#pagebreak()
+
+== Internal Functions (IFs) <bbif-top>
+
+Internal Functions are the textual commands that BUZBEE interprets from the
+command line to execute the user's wish. Internal Functions are canonically
+listed in alphabetical order. Below in @bbif-table is a list of available IFs.
+
+#figure(
+  table(
+    columns: (auto, auto, 1fr),
+    inset: 10pt,
+    align: center,
+    fill: (_, y) =>
+      if calc.odd(y) { luma(250) }
+      else { white },
+    table.header(
+      [*Name* (pg. no.)], [*Command Token*], [*Description*]
+    ),
+    [`CALL` (#ref(<bbif-call>, form: "page"))],
+    [`$00`],
+    [Call a resident routine in the MPU's address space.],
+    [`HELP` (#ref(<bbif-help>, form: "page"))],
+    [`$01`],
+    [Display a summary of known commands.],
+    [`PEEK` (#ref(<bbif-peek>, form: "page"))],
+    [`$02`],
+    [Dumps memory from the MPU's address space to the terminal.],
+    [`POKE` (#ref(<bbif-poke>, form: "page"))],
+    [`$03`],
+    [Overwrites memory in the MPU's address space.],
+    [`SREC` (#ref(<bbif-srec>, form: "page"))],
+    [`$04`],
+    [Switches into Motorola S-Record receive mode.],
+  ),
+  caption: [Table of IFs],
+) <bbif-table>
+
+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 described in @bbinternals.
+
+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
+hex are encoded as their corresponding bytes directly. The token buffer
+mechanics are described more in @bbinternals. Subcommands are also hashed into
+tokens.
+
+#pagebreak()
+
+// Function for creating IF page headers
+#let _ifpagehead(
+  desc: none,
+  syntax: none,
+  params: (),
+) = {
+  smallcaps[#desc]
+  parbreak()
+  [Syntax: #syntax]
+  parbreak()
+  [Parameters: ]
+  if params.len() > 0 {
+    for (param, desc) in params [
+      - #raw("<" + upper(param) + ">"): #desc
+    ]
+  } else {
+    text(style: "italic")[N/A]
+  }
+}
+
+==== IF: `CALL` <bbif-call>
+
+#_ifpagehead(
+  desc: "Calls a resident routine in the MPU's address space.",
+  syntax: [`CALL <PTR>`],
+  params: (
+    ptr: "An absolute pointer to a position in the 6309 MPU's memory map.",
+  ),
+)
+
+Call takes an absolute pointer into the MPU's address space to call as if it
+were a subroutine using `JSR`.
+
+// TODO: For when CHIBI PC-09 Prototype #2 comes out or whenever we get banking
+// add it here "Special care must be taken to properly bank in the correct
+// memory banks before executing this command." yadda yadda
+
+#pagebreak()
+
+==== IF: `HELP` <bbif-help>
+
+#_ifpagehead(
+  desc: "Displays a summary of available IFs.",
+  syntax: [`HELP`],
+  params: ()
+)
+
+`HELP` does what it says on the tin. It should be noted that between Git tags of
+the firmware the message displayed by this may be incomplete or innaccurate.
+Internally all this does is print a string with the UART using the `POUTZSTR`
+BIOS routine.
+
+#pagebreak()
+
+==== IF: `PEEK` <bbif-peek>
+
+#_ifpagehead(
+  desc: "Dumps memory from the MPU's address space to the terminal.",
+  syntax: [`PEEK <BASE> [<HIGH>]`],
+  params: (
+    base: [
+      The address (two bytes) of the byte to dump or the base (lower bound)
+      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>`. (two bytes)
+    ],
+  )
+)
+
+Peeking memory causes the MPU to read the requested bytes and dump them to the
+screen.
+
+#pagebreak()
+
+==== IF: `POKE` <bbif-poke>
+
+#_ifpagehead(
+  desc: "Writes values to the MPU's address space.",
+  syntax: [`POKE <ADDR> <BYTES>`],
+  params: (
+    addr: "The base (low) address (two bytes) to start writing bytes from.",
+    bytes: "The bytes to write into memory separated by whitespace.",
+  )
+)
+
+Poking memory causes the MPU to overwrite the bytes at `<ADDR>` with the bytes
+given in `<BYTES>`.
+
+#pagebreak()
+
+==== IF: `SREC` <bbif-srec>
+
+#_ifpagehead(
+  desc: "Switches into Motorola S-Record receive mode.",
+  syntax: [`SREC`],
+  params: (),
+)
+
+Motorola S-Record mode is currently a stub.
+
+#pagebreak()
+
+=== External Functions (EFs) <bbef-top>
+
+External functions are any native user code that can be called with `CALL` (see
+@bbif-call). This mechanism is usable to run any code or routine in memory as
+though interactively using the MPU's `JSR` instruction.
+
+== BUZBEE Reserved Memory Regions <res-mem>
+
+BUZBEE uses memory in the 0200-02FF page. A table of the layout of this memory
+is provided. The memory is laid out in a packed structure starting at 0200.
+
+#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()
+
+== BUZBEE Internals and Modding <bbinternals>
 
 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
+for more simply passing parameters to IFs (see @bbif-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.
 

linkscript

@@ -1,9 +1,19 @@
+; BIOS
 section RESET load 8000
 section SERIAL
-section MEMTEST
 
+; BIOS Interface and Utilities
+section BIOSINT
+
+; BUZBEE Monitor
 section BUZBEE
 section BBHASHES
 
+; Onboard programs
+section MEMTEST load 9000
+
+; Static Data
 section VECTORS high 100000
 section VERSION high
+
+entry 8000

makefile

@@ -34,7 +34,7 @@ LDFLAGS := -f srec -m map.txt -s linkscript
 # ------------------------------------------------------------------------------
 
 docs: docs/*.typ
-	typst compile docs/buzbee.typ
+	typst compile docs/firmware.typ
 
 all: $(TARGROM)
 

src/biosint.inc

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

src/biosint.s

@@ -0,0 +1,52 @@
+; CHIBI PC-09 Prototype #1 Boot ROM -- BIOS Interface
+; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
+; Licensed under MIT
+
+  INCLUDE "serial.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
+CHIBIOPTRTBL
+  fdb CIOPOUTCHAR ; serial/POUTCHAR wrapper
+  fdb CIOPOUTZSTR ; serial/POUTZSTR wrapper
+  fdb CIOPINCHAR  ; serial/CIOPINCHAR wrapper
+
+; POUTCHAR wrapper
+; @param B: char to write
+CIOPOUTCHAR
+  tfr b,a
+  jsr POUTCHAR
+  rti
+
+; POUTZSTR wrapper
+; @param X: start of zstring
+CIOPOUTZSTR
+  jsr POUTZSTR
+  rti
+
+; PINCHAR
+; @return A: filled with char from RX buffer or NUL if no char is ready
+; @return B: filled with LSR status codes masked with $9F
+CIOPINCHAR
+  jsr PINCHAR
+  rti

src/buzbee.s

@@ -44,6 +44,7 @@ BUZBEE
   bsr INPLOOP        ; Fill input buffer.
   cmpy #0            ; No data?
   beq BUZBEE         ;  Try again...
+  lbsr MKINSENSITIVE ; Make the input buffer case insensitive
   lbsr TOKENIZE      ; Try to tokenize the input buffer
   lbsr RUNIF         ; Execute token buffer, handling any errors
   bra BUZBEE         ; Repeat
@@ -127,6 +128,21 @@ 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
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
 ;; Hex Conversion and Printing Routines
@@ -301,7 +317,8 @@ RUNIF
   beq NOTOK@
   ldx #0           ; Counting up from zero
   lda BBVAR.tokens ; Load token
-  tfr a,b          ; Get the index in D
+  tfr a,d          ; Get the index in D
+  clra
   asld             ; Cheaply << to get *2, pointer size
   tfr d,x          ; Move to X so we can use indexed mode with the offset
   jmp [IFPTRTBL,x] ; Select IF

src/progs.s

@@ -1,23 +1,24 @@
-; CHIBI PC-09 Prototype #1 Boot ROM -- Memory Testing Routines
+; CHIBI PC-09 Prototype #1 Boot ROM -- Onboard Programs or BUZBEE "EFs"
 ; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
 ; Licensed under MIT
 
+; These are onboard programs with fixed locations in the linkerscript for
+; starting from a machine language monitor
+
   INCLUDE "hardware.inc"
   INCLUDE "serial.inc"
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
-;; Memory Testing Routines
+;; Memory Testing Routine
 ;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
   SECTION MEMTEST
 
-  EXPORT RAMTEST
-
 ; RAM testing routine. Ported to 6809 from 6800, based on source for ROBIT-2 for
 ; MIKBUG.
-RAMTEST
+ROBIT
   ldx #STACK_TOP+1     ; bottom of testable SRAM, $0200
 AGAIN@                 ; Store 1 in memory
   lda #1               ; Set [X] to 1
@@ -41,4 +42,17 @@ ERR@                   ; Write out error indicator
 PASS@                  ; Pass test
   ldb #'P
   jsr POUTCHAR
-  rts
+  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/reset.s

@@ -4,7 +4,6 @@
 
   INCLUDE "buzbee.inc"
   INCLUDE "hardware.inc"
-  INCLUDE "memtest.inc"
   INCLUDE "serial.inc"
   INCLUDE "version.inc"
 
@@ -36,13 +35,14 @@ BOOTSCR
   lda #13      ; 9600 baud
   ldb #%11     ; 8N1
   jsr INITUART ; Initialize serial console
-  PZSTR VERMSG ; Print version information
+  PZSTR VERMSG ; Since we know the addr of VERMSG at link time we can avoid
+               ; calling out to CHIBIO
 
 ; Hand off control to the BUZBEE monitor and print notification of leaving the
 ; firmware
 ENTERMON
-  PZSTR TXTRUN
-  jmp BUZBEE
+  PZSTR TXTRUN ; Print run message
+  jmp BUZBEE   ; Jump into a monitor program
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
@@ -51,4 +51,5 @@ ENTERMON
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 TXTRUN
-  fcn "<3RUN<3"
+  fcc "<3RUN<3"
+  fcb $0D,$0A,$00

src/vecs.s

@@ -2,6 +2,7 @@
 ; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
 ; Licensed under MIT
 
+  INCLUDE "biosint.inc"
   INCLUDE "reset.inc"
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -14,7 +15,7 @@
 
 VECTORS
   fdb $0000  ; Exception
-  fdb $0000 ; SWI3
+  fdb CHIBIO ; SWI3
   fdb $0000  ; SWI2
   fdb $0000  ; FIRQ
   fdb $0000  ; IRQ