cuppar/assembler

Hack Assembler

Hack Assembler

Hack assembler process the output from Jack compiler backend vmtranslator.

• assembler transfer a XXX.asm assembly program to a XXX.hack file.
• The XXX.hack file is the Hack machine code file, it can be execution by Hack machine(A simple von Neumann machine).

Example

$ assembler Max.asm

Assembly code

Max.asm

// Computes R2 = max(R0, R1)  (R0,R1,R2 refer to RAM[0],RAM[1],RAM[2])

   @R0
   D=M              // D = first number
   @R1
   D=D-M            // D = first number - second number
   @OUTPUT_FIRST
   D;JGT            // if D>0 (first is greater) goto output_first
   @R1
   D=M              // D = second number
   @OUTPUT_D
   0;JMP            // goto output_d
(OUTPUT_FIRST)
   @R0             
   D=M              // D = first number
(OUTPUT_D)
   @R2
   M=D              // M[2] = D (greatest number)
(INFINITE_LOOP)
   @INFINITE_LOOP
   0;JMP            // infinite loop

Machine code

Max.hack

0000000000000000
1111110000010000
0000000000000001
1111010011010000
0000000000001010
1110001100000001
0000000000000001
1111110000010000
0000000000001100
1110101010000111
0000000000000000
1111110000010000
0000000000000010
1110001100001000
0000000000001110
1110101010000111