88 lines
1.4 KiB
Plaintext
88 lines
1.4 KiB
Plaintext
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const KBD_STATUS 0x1ffc
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const KBD_CODE 0x1ffe
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const VCD 0x2000
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const FL_EQ 0x2
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const FL_EQ 0x4
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const KBD_FLAG_IS_RELEASE 0x1
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mov rsp, 0x1000
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mov rbp, rsp
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mov r0, 512
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mov r1, 1
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dskr r0, r1
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; setup video character display (VCD)
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; descriptor table structure:
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; [addr + 0] memory map base
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mov r0, VCD
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mov [0x700], r0
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lvcd 0x700
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; setup keyboard (KBD)
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; descriptor table structure:
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; [addr + 0] status address
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; [addr + 2] keycode address
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; [addr + 4] keyboard interrupt handler
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mov r0, KBD_STATUS
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mov [0x702], r0
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mov r0, KBD_CODE
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mov [0x704], r0
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mov r0, key_press_int
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mov [0x706], r0
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lkbd 0x702
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; character counter
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mov r0, 0
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mov [0x600], r0
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main_loop:
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hlt
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jmp main_loop
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key_press_int:
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mov r0, [KBD_STATUS]
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and r0, r0, KBD_FLAG_IS_RELEASE
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jnz r0, .leave
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mov r0, [0x600]
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add r0, r0, VCD
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mov r1, [KBD_CODE]
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cmp r1, 44 ; spacebar
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mov r2, rfl
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and r2, r2, FL_EQ
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jnz r2, .incr
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add r1, r1, 61
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mov byte [r0], r1
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.incr:
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mov r0, [0x600]
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add r0, r0, 1
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mov [0x600], r0
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.leave:
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reti
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;scancode_to_char:
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; cmp r1, 61
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;
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; mov r2, rfl
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; and r2, r2, FL_LT
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; jnz .not_letter
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;
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; ; if r1 > 86 { goto .not_letter }
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; cmp r1, 86
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; mov r2, rfl
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; xor r2, 0xffff
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; and r2, r2, FL_EQ | FL_LT
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;
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;
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; mov r4, rfl
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; and r4, r4, FL_EQ
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; shr r4, r4, 2
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