f3c7ac9696
Instead of using the bootsector to load a bootloader, just put the bootloader in the ROM and call it a day. It looks for a file on the SD card in the root directory named `kernel.bin` and loads it into memory. This is not a perfect solution, as the kernel will grow larger and the kernel load address will have to change. At this point I could add back the bootloader, but that is for later. Also the bootloader is just a copy of the kernel, so that can be trimmed down a lot.
60 lines
1.0 KiB
ArmAsm
60 lines
1.0 KiB
ArmAsm
.importzp sp, sreg
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.import _uart_txb_block
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.import _lastchar
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.export _cputc
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.export gotoxy
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.export _clrscr
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.export _cgetc
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.autoimport on
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.code
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; void __fastcall__ cputc (char c);
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_cputc:
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jsr _uart_txb_block
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cmp #$0a
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bne @1
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lda #$0d
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jsr _uart_txb_block
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@1: rts
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; void __fastcall__ gotoxy (unsigned char x, unsigned char y);
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gotoxy:
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phx
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phy
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tay ; Move y position to y
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lda (sp)
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tax ; Move x position to x
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lda #$1b
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jsr _uart_txb_block
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lda #'['
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jsr _uart_txb_block
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tya
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jsr _uart_txb_block
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lda #';'
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jsr _uart_txb_block
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txa
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jsr _uart_txb_block
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lda #'H'
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jsr _uart_txb_block
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ply
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plx
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rts
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_clrscr:
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phx
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lda #$1b
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jsr _uart_txb_block
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lda #'c'
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jsr _uart_txb_block
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pla
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rts
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_cgetc:
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@2: lda _lastchar
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beq @2
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stz _lastchar
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rts |