; r12 will be the char of the value of the current ptr
li64 r12, 0
; r13 will be the offset into the lisp_expr label
li64 r13, 0
;; r253 will be the offset from the stack pointer specified by the spec to be r254
li64 r253, 0


ldr r12, r13, lisp, 1

loop:
    ; zero r15
    li64 r15, 0

    ; Check if the char is a (
    li64 r15, 0x28
    ; if equal jump to open_paren
    jeq r12, r15, open_paren

    ; check if the char is )
    li64 r15, 0x29
    ; if equal jump to closed_paren
    jeq r12, r15, closed_paren

    ; move the char into r2
    cp r2, r12
    ; push the char onto the stack
    jmp push_u64_stack

    jmp loop

tx


;; push r2 into the stack
push_u64_stack:
    ;; store r2 -> r254 + r253 with size 8
    st r2, r254, r253, 8
    li64 r252, 8
    add64 r253, r253, r252
    jmp inc_ptr_ld_char


;; pop the head of the stack into r2
pop_u64_stack:
    ;; load r2 <- r254 + r253 with size 8
    ld r2, r254, r253, 8
    li64 r252, 8
    sub64 r253, r253, r252
    ; jmp inc_ptr_ld_char

inc_ptr_ld_char:
    ; inc ptr
    addi64 r13, r13, 1
    ; load next char
    ldr r12, r13, lisp, 1
    jmp loop

open_paren:
    jmp inc_ptr_ld_char

closed_paren:
    jmp log_lisp_error

eval_stack:
    jmp pop_u64_stack
    jmp panic

panic:
    jmp log_lisp_error

lisp:
    .db "(+ 1 2 3 4 5 6 7 8 9 10)"
    .db "(define a (λ () (+ 1 2 3)))"
    .db "(a)"

builtin_lambda:
    .db "λ"

builtin_quote:
    .db "'"

log_lisp_error:
    li64 r1, 3
    li64 r2, 1
    lra16 r3, r0, lisp_error
    li64 r4, 32
    eca
    tx

lisp_error:
    .db "Some sort of error has occured."
    .db 0