feat(boot): new baud setup routine

code/boot/.gitignore

@@ -5,6 +5,3 @@
 *.s19
 map.txt
 build/
-
-# Build system generated files
-src/version.s

code/boot/README.md

@@ -15,14 +15,12 @@ Make makefile is provided for building on Linux.
 To generate an S-Record run:
 
 ```sh
-make generate
 make boot.s19
 ```
 
 To generate a binary run:
 
 ```sh
-make generate
 make
 ```
 

code/boot/genver.sh

@@ -1,33 +0,0 @@
-#!/usr/bin/env sh
-
-# Script to generate version information
-
-# Current git tag
-TAG="$(git describe --always --dirty --tags)"
-DATE="$(date)"
-
-# Output filename
-OUTFILE='src/version.s'
-
-sed -e "s/<TAG>/$TAG/g" -e "s/<DATE>/$DATE/g" <<EOF > "$OUTFILE"
-; CHIBI PC-09 Prototype #1 Boot ROM -- Version Information
-; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
-; Licensed under MIT
-
-; This file generated by genver.sh
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;; Boot ROM Version & Build Information
-;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-  SECTION VERSION
-
-  EXPORT VERMSG
-
-VERMSG
-  fcc "CHIBI PC-09 BOOT ROM <TAG>"
-  fcb \$0A
-  fcn "BUILT <DATE>"
-EOF

code/boot/linkscript

@@ -3,4 +3,3 @@ section SERIAL
 section MEMTEST
 
 section VECTORS high 100000
-section VERSION high

code/boot/makefile

@@ -1,6 +1,6 @@
 # Makefile for CHIBI PC-09 Firmware
 
-.PHONY: generate all clean
+.PHONY: all clean
 .IGNORE: clean
 .DEFAULT_GOAL := all
 
@@ -13,7 +13,6 @@ TARGREC  := $(TARGET).s19
 TARGROM  := $(TARGET).bin
 SRCDIR   := src/
 BUILDDIR := build/
-GENS     := $(SRCDIR)version.s
 SRCS     := $(wildcard $(SRCDIR)*.s)
 OBJS     := $(patsubst $(SRCDIR)%.s,$(BUILDDIR)%.o,$(SRCS))
 INCS     := $(wildcard $(SRCDIR)*.inc)
@@ -48,12 +47,6 @@ $(OBJS): $(BUILDDIR)%.o : $(SRCDIR)%.s
 	-@mkdir -p $(BUILDDIR)
 	$(AS) $(ASFLAGS) -o $@ $<
 
-generate: $(GENS)
-
-$(GENS):
-	./genver.sh
-
 clean:
 	@echo 'Cleaning up intermediary files...'
 	@rm -rv $(TARGROM) $(TARGREC) map.txt $(BUILDDIR)
-	@rm -rv $(GENS)

code/boot/src/reset.s

@@ -26,7 +26,7 @@ NEXT@
   leax 1,x
   cmpx #STACK_DEPTH  ; See if we're at the top of the stack yet
   blo NEXT@          ; Loop if we aren't at the end yet
-  lds #STACK_TOP     ; Set S to top of newly cleared stack
+  lds STACK_TOP      ; Set S to top of newly cleared stack
 
 SERINIT
   ; 8n1 Serial Enable DLAB
@@ -40,8 +40,8 @@ SERINIT
   sta UART_LCR
   lda #(UARTF_MCR_RTS) ; Enable Request-to-Send
   sta UART_MCR
-  lda #'H              ; send 'H'
-  sta UART_BUFR
+  lda #'H               ; send 'H'
+  sta UART_THR
 
 WAIT
   sync                 ; Wait for interrupts

code/boot/src/serial.s

@@ -12,9 +12,25 @@
 
   SECTION SERIAL
 
+  EXPORT SETBAUD
   EXPORT OUTCHAR
   EXPORT OUTSTR
 
+; Initializes the UART.
+; @param d: new divisor
+SETBAUD
+  pshs a              ; Preserve A
+  lda UART_LCR        ; Set only the DLAB bit
+  ora #UARTF_LCR_DLAB
+  sta UART_LCR
+  puls a
+  sta UART_DLM        ; Store new divisor
+  stb UART_DLL
+  lda UART_LCR        ; Reset DLAB
+  anda #$FE
+  sta UART_LCR
+  rts
+
 ; Writes a char to the UART in non FIFO mode, preserves A.
 ; @param b: char to write
 OUTCHAR
@@ -23,7 +39,7 @@ NOTREADY@
   lda UART_LSR         ; if LSR.THRE == 1 then write
   anda UARTF_LSR_THRE
   bne NOTREADY@        ; Loop if UART not ready yet
-  stb UART_BUFR        ; Write char
+  stb UART_THR         ; Write char
   puls a               ; Restore A
   rts
 
@@ -39,7 +55,7 @@ NOTREADY@              ; Loop point for UART waiting
   lda UART_LSR         ; Wait for UART to be ready
   anda UARTF_LSR_THRE
   bne NOTREADY@
-  stb UART_BUFR        ; Actually do our write
+  stb UART_THR         ; Actually do our write
   bra OUTSTR           ; Reset for the next char
 END@                   ; Jump point for end of routine
   rts