// If (R0 <= 0) goto END else n = R0
@R0
D=M
@END
D;JLE
@n
M=D
// addr = base address of first screen row
@SCREEN
D=A
@addr
M=D
(LOOP)
// RAM[addr] = -1
@addr
A=M
M=-1
// addr = base address of next screen row
@addr
D=M
@32
D=D+A
@addr
M=D
// decrements n and loops
@n
MD=M-1
@LOOP
D;JGT
(END)
@END
0;JMP