SECD machine

Attempt on implementing a secd virtual machine without any knowledge in virtual machines. The machine is adapted from original paper The Mechanical Evaluation of Expressions with slight changes.

Instructions

Building

The project uses nothing but c++ standard library and is built with cmake. So, simple

$ mkdir build
$ cmake -B build
$ make -C build

will be enough.

Usage

There are two targets: secd - the machine itself, and asm - the assembler to get machine code to execute. For the test, a factorial program is present in the repo, it calculates the factorial of 7 recursively.

One can test it with

$ ./build/asm fact.asm fact.func
$ ./build/secd fact.func

Examples

There will be some samples of code to compile and test on the secd machine.

Factorial

The factorial program is present in the repo and duplicated in the README here.

func:
    LDE x
    LDC 0
    EQ
    SEL then else
    STP

then:
    LDC 1
    STP

else:
    LDE f
    LDC 1
    LDE x
    SUB
    LDE f
    AP
    LDE x
    MUL
    STP

main:
    LDF func (f x)
    ST f
    LDE f
    LDE read
    AP
    LDE f
    AP
    LDE print
    AP
    STP

cons, car, cdr

The machine does not have built-in list instructions, therefore they should be implemented manually

dispatch:
LDE c
LDC 0
EQ
SEL then else
STP

then:
LDE x
STP

else:
LDE y
STP

cons:
LDE x
LDE y
LDF dispatch // closure created
STP

car:
LDC 0
LDE l
AP
STP

cdr:
LDC 1
LDE l
AP
STP