start working on boot code, move things around

2024-11-21 10:40:59 -05:00
parent fc115752e6
commit dcc1bea405
15 changed files with 79 additions and 6 deletions
--- a/code/boot/boot.s
+++ b/code/boot/boot.s
@@ -0,0 +1,44 @@
+; CHIBI PC-09 Prototype #1 Boot ROM
+; (Copyright (c) 2024 Amber Zeller
+
+; UART registers
+UART = $7F00
+
+; When DLAB = 0
+BUFR = UART    ; TX/RX Buffer (Read for RX, Write for TX)
+IER = UART + 1 ; Interrupt Enable Register
+IIR = UART + 1 ; Interrupt Enable Register (Upon Read)
+; When DLAB = 1
+DLL = UART     ; Divisor Latch (LSB)
+DLM = UART + 1 ; Divisor Latch (MSB)
+
+FCR = UART + 2 ; FIFO Control Register (Upon Write)
+LCR = UART + 3 ; Line Control Register
+MCR = UART + 4 ; MODEM Control Register
+LSR = UART + 5 ; Line Status Register
+MSR = UART + 6 ; MODEM Status Register
+SCR = UART + 7 ; Scratch Register (Not for control just spare RAM)
+
+;  SECTION code
+
+  org $8000
+
+RESET:
+  sta $cc
+  jmp RESET
+  fdb RESET
+
+;  ENDSECTION
+
+;  SECTION vectors
+  org $FFF0
+  ; Reset/Interrupt Vectors
+  fdb  $0000 ; Reserved
+  fdb  $0000 ; SWI3
+  fdb  $0000 ; SWI2
+  fdb  $0000 ; FIRQ
+  fdb  $0000 ; IRQ
+  fdb  $0000 ; SWI
+  fdb  $0000 ; NMI
+  fdb  RESET ; Reset
+;  ENDSECTION