blob: 1775a0a5f9a8207fac53eba68fc50e039f61ebdc [file] [log] [blame]
;;; scratch.s -- ideas for how code generation will work
;; (defun lisp-function (A B)
;; (let ((local-var (whatever)))
;; (whatever local-var (something-else 4))))
;;
;; This means the stack looks like this:
;; B_value
;; B_tag
;; A_value
;; A_tag
;; result pointer
;; return pointer <---- esp
lisp_function:
push ebp ; Now ebp can be used as an offset
mov ebp, esp
sub esp, 16 ; 1 var, 1 temporary
;; Now, call `whatever' with no arguments
;; For now we will do no register allocation, so don't even
;; bother saving anything.
lea eax, [ebp - 8]
push eax ; Return address
call whatever
;; Now we need to evaluate (something-else 4) and store it in a
;; temporary variable.
;; First set up the literal 4
push 4 ; The value
push 0x20000000 ; Type tag and length
;; Then set up the return address
lea eax, [ebp - 16]
push eax
call something_else ; Result stored in temporary
;; Next function: `whatever'
push [ebp - 12] ; The temporary
push [ebp - 16]
push [ebp - 8] ; The variable
push [ebp - 4]
push [ebp + 4] ; The function's return address
call whatever
ret