Rename bootloader to bios, add actual bootloader

2023-07-31 19:58:32 -07:00
parent 5128fe64b6
commit 18b8ac7ccf
29 changed files with 168 additions and 138 deletions
--- a/sw/bios/devices/uart.s
+++ b/sw/bios/devices/uart.s
@@ -0,0 +1,36 @@
+.include "io.inc65"
+
+.importzp sp, sreg
+
+.export _uart_txb, _uart_txb_block
+.export _uart_rxb
+.export _uart_status
+
+.autoimport	on
+
+.code
+
+; @in A: byte to transmit
+; Transmits a byte over the UART
+_uart_txb:
+        sta UART_TXB        ; Just write value, don't wait
+        rts
+
+_uart_txb_block:
+        pha
+        sta UART_TXB        ; Write value
+@1:     lda UART_STATUS     ; Wait for status[1] to be 0
+        bit #$02
+        bne @1
+        pla
+        rts
+
+_uart_rxb:
+        lda UART_RXB        ; Read value
+        ldx #$00
+        rts
+
+_uart_status:
+        lda UART_STATUS
+        ldx #$00
+        rts