amberisvibin/chibi-pc09
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minimum functional bootcode

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This commit is contained in:
Amber
2024-11-21 12:15:27 -05:00
parent dcc1bea405
commit cea8a54ebf
3 changed files with 31 additions and 16 deletions
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BIN
code/boot/boot.bin
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38
code/boot/boot.s
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@@ -6,27 +6,41 @@ UART = $7F00
; When DLAB = 0 ; When DLAB = 0
BUFR = UART ; TX/RX Buffer (Read for RX, Write for TX) BUFR = UART ; TX/RX Buffer (Read for RX, Write for TX)
IER = UART + 1 ; Interrupt Enable Register IER = UART+1 ; Interrupt Enable Register
IIR = UART + 1 ; Interrupt Enable Register (Upon Read) IIR = UART+1 ; Interrupt Enable Register (Upon Read)
; When DLAB = 1 ; When DLAB = 1
DLL = UART ; Divisor Latch (LSB) DLL = UART ; Divisor Latch (LSB)
DLM = UART + 1 ; Divisor Latch (MSB) DLM = UART+1 ; Divisor Latch (MSB)
FCR = UART + 2 ; FIFO Control Register (Upon Write) FCR = UART+2 ; FIFO Control Register (Upon Write)
LCR = UART + 3 ; Line Control Register LCR = UART+3 ; Line Control Register
MCR = UART + 4 ; MODEM Control Register MCR = UART+4 ; MODEM Control Register
LSR = UART + 5 ; Line Status Register LSR = UART+5 ; Line Status Register
MSR = UART + 6 ; MODEM Status Register MSR = UART+6 ; MODEM Status Register
SCR = UART + 7 ; Scratch Register (Not for control just spare RAM) SCR = UART+7 ; Scratch Register (Not for control just spare RAM)
; SECTION code ; SECTION code
org $8000 org $8000
RESET: RESET:
sta $cc ; UART Setup
jmp RESET lda %11000001 ; 8n1 serial, enable DLAB
fdb RESET sta LCR
lda $00 ; Set divisor to 12 (9600 baud)
sta DLL
lda $0C
sta DLM
lda %11000000 ; 8n1 serial, disable DLAB
sta LCR
lda %01000000 ; Enable RTS
sta MCR
lda 'H ; send H
STA BUFR
; ENDSECTION ; ENDSECTION

5
code/boot/boot.s19
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@@ -1,5 +1,6 @@
S01800005B6C77746F6F6C7320342E32335D20626F6F742E73BF S01800005B6C77746F6F6C7320342E32335D20626F6F742E73BF
S10A800097CC7E8000800094 S113800096C1B77F039600B77F00960CB77F0196A1
S1118010C0B77F039640B77F049648B77F0041
S113FFF0000000000000000000000000000080007D S113FFF0000000000000000000000000000080007D
S5030002FA S5030003F9
S9030000FC S9030000FC