diff --git a/code/boot/src/boot.s b/code/boot/src/boot.s index 7f13307..408ced3 100644 --- a/code/boot/src/boot.s +++ b/code/boot/src/boot.s @@ -10,6 +10,7 @@ ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + SECTION "Reset" ORG ROM_BASE RESET @@ -36,12 +37,74 @@ WAIT nop bra WAIT + SECTION "Serial" + +; Writes a char to the UART in non FIFO mode, preserves A. +; @param b: char to write +OUTCHAR + pshs a ; Preserve A +1 + lda UART_LSR ; if LSR.THRE == 1 then write + anda UARTF_LSR_THRE + bne 1B ; Loop if UART not ready yet + stb UART_BUFR ; Write char + puls a ; Restore A + rts + +; Writes a null terminated string to the UART in non FIFO mode, clobbers A and +; B. +; @param x: null terminated string start address. +OUTSTR + ldb x ; Get the next value from X + cmpb #$00 ; Make sure that mother is non-null + beq 2F + leax 1,x ; Increment X for our next char +1 ; Loop point for UART waiting + lda UART_LSR ; Wait for UART to be ready + anda UARTF_LSR_THRE + bne 1B + stb UART_BUFR ; Actually do our write + bra OUTSTR ; Reset for the next char +2 ; Jump point for end of routine + rts + + SECTION "Memtest" + +; RAM testing routine. Ported to 6809 from 6800, based on source for ROBIT-2 for +; MIKBUG. +RAMTEST + ldx #SRAM_BASE +1 ; Store 1 in memory + lda #1 ; Set [X] to 1 + sta 0,x + cmpa 0,x ; If failed print out an error indicator + bne 3F +2 ; Loop point for next address + asla ; Shift A and [X] left + asl 0,x + cmpa 0,x ; Compare A and [X] + bne 3F + cmpa #$80 ; Only test up to $80 + bne 2B ; Loop if not $80 + cmpx #$60FF ; Compare X to end of RAM + beq 4F ; Finish if we're at the end + leax 1,x ; Increment X + bra 1B +3 ; Write out error indicator + ldb #'X + jsr OUTCHAR +4 ; Pass test + ldb #'P + jsr OUTCHAR + rts + ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; Interrupt and Reset Vectors ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + SECTION "Vectors" ORG VECS_BASE VECTORS