89 lines
1.4 KiB
ArmAsm
89 lines
1.4 KiB
ArmAsm
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.define mon
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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mon:
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popl saveret, *RR14
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pop R0, *RR14 ! iocode
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cp R0, $1 ! exit
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jr NE, read
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inc R15, $2
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sc $EXIT
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read: cp R0, $3 ! read
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jr NE, write
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pop R0, *RR14 ! dummy; all input from stdin
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pop R1, *RR14 ! ptr to buffer
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pop R2, *RR14 ! nr of bytes to be read
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ld R3, R1
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cp R2, $0
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jr EQ, 6f
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1: sc $2 ! read character into RL0
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cpb RL0, $004 ! \^D
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jr EQ, 6f
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cpb RL0, $015 ! \cr
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jr NE, 2f
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ldb RL0, $012
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2: sc $4 ! echo
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cpb RL0, $010 ! \^H
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jr NE, 3f
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cp R1, R3
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jr EQ, 5f
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dec R1
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jr 5f
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3: cpb RL0, $0100 ! \@
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jr NE, 4f
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ld R1, R3
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ldb RL0, $012
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sc $4
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jr 5f
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4: ldb 0(R1), RL0
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inc R1
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cpb RL0, $012 ! \nl
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jr EQ, 6f
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5: djnz R2, 1b
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6: sub R1, R3 ! nr of bytes read
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push *RR14, R1
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push *RR14, $0
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jr retu
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write: cp R0, $4 ! write
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jr NE, open
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pop R0, *RR14 ! dummy; all output to stdout
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pop R1, *RR14 ! ptr to buffer
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pop R2, *RR14 ! nr of bytes to be written
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ld R3, R2
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cp R2, $0
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jr EQ, 8f
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9: ld R0, $5000 ! counter to delay printing a little
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7: djnz R0, 7b
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ldb RL0, 0(R1)
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sc $4
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inc R1
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djnz R2, 9b
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8: sub R3, R2 ! nr of bytes written
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push *RR14, R3
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push *RR14, $0
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jr retu
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open: cp R0, $5 ! open
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jr close
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jr NE, close
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ld *RR14, $0
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ld 2(R15), $0
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jr retu
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close: cp R0, $6 ! close
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jr NE, ioctl
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ld *RR14, $0
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jr retu
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ioctl: cp R0, $54 ! ioctl
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jr NE, err
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inc R15, $4
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ld *RR14, $0
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retu: ldl RR2, saveret
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jp *RR2
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err: push *RR14, saveret
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push *RR14, $EBADMON
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calr trp
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ret
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