Stack Machines

• Instruction set:

  add, sub, mult, div . . . Top of stack (TOS) and TOS+1 are implicit
  
  push A, pop A TOS is implicit operand, one explicit operand
  

Example: a*b - (a+c*b)

push a

push b
mult
push a
push c
push b
mult
add
sub
9 instructions

A

B

A

A*B

-

+

a

a

b

*

b

*

c

A*B

A*B

A*B

A

A

C

A*B

A

A*B

A

C

B

C*B

+ *

- + *

time

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