.ORIG	x3000
input		LEA r0, text
		PUTS
		LEA r1, number
		AND r2, r2, #0
		ADD r2, r2, #10

check		GETC
		ADD r1, r0, #0
		ADD r1, r1, #1
		OUT
		ADD r1, r0, #0
		LD r3, plus
		ADD r0, r1, r3
		BRz pos
		LD r3, minus
		ADD r0, r1, r3
		BRz neg
		LEA r0, invalid
		PUTS
		BRnzp input


pos
		GETC
		ADD r1, r0, #0
		ADD r1, r1, #1
		OUT
		ADD r1, r0, #0
		ADD r0, r0, #-10
		BRz done

		LD r4, asciimin
		ADD r1, r1, r4

times1		ADD r1, r1, r1
		ADD r2, r2, #-1
		LDR r0, r2, #0
		BRz pos
		BRnp times1

		LEA r2, masks
loop		LDR r3, r2, #0
		ADD r2, r2, #1
		AND r0, r1, r3

		BRnz else
		LD r0, ascii1
		BRnzp finish
else		LD r0, ascii0
finish		OUT
		LEA r0, space
		PUTS
		ADD r4, r4, #1
		ADD r0, r4, #-16
		BRn loop
		BRnzp done

neg
		GETC
		ADD r1, r0, #0
		ADD r1, r1, #1
		OUT
		ADD r1, r0, #0
		ADD r0, r0, #-10
		BRz done

		LD r4, asciimin
		ADD r1, r1, r4

times2		ADD r1, r1, r1
		ADD r2, r2, #-1
		LDR r0, r2, #0
		BRz neg
		BRnp times2

		LEA r2, masks
loop2		LDR r3, r2, #0
		ADD r2, r2, #1
		AND r0, r1, r3

		BRnz else2
		LD r0, ascii1
		BRnzp finish2
else2		LD r0, ascii0
finish2		OUT
		LEA r0, space
		PUTS
		ADD r4, r4, #1
		ADD r0, r4, #-16
		BRn loop2
done
		HALT

number		.BLKW 99
ascii0		.FILL x30
ascii1		.FILL x31
asciimin	.FILL x-30
times10		.FILL #10
minus		.FILL x-2D
plus		.FILL x-2B
space		.STRINGZ " "
text		.STRINGZ "Enter an integer between -511 and +511: "
invalid		.STRINGZ "\nThe input is invalid.\n"

masks		.FILL b1000000000000000
		.FILL b0100000000000000
		.FILL b0010000000000000
		.FILL b0001000000000000
		.FILL b0000100000000000
		.FILL b0000010000000000
		.FILL b0000001000000000
		.FILL b0000000100000000
	   	.FILL b0000000010000000
        	.FILL b0000000001000000
        	.FILL b0000000000100000
        	.FILL b0000000000010000
        	.FILL b0000000000001000
        	.FILL b0000000000000100
        	.FILL b0000000000000010
        	.FILL b0000000000000001

		.END