fn evaluate defs: (addr handle function), bindings: (addr table), scratch: (addr line), end: (addr word), out: (addr int-stack) { var line/eax: (addr line) <- copy scratch var word-ah/eax: (addr handle word) <- get line, data var curr/eax: (addr word) <- lookup *word-ah var curr-text-storage: (stream byte 0x10) var curr-text/edi: (addr stream byte) <- address curr-text-storage clear-int-stack out $evaluate:loop: { # precondition (should never hit) compare curr, 0 break-if-= # update curr-text emit-word curr, curr-text $evaluate:process-word: { # if curr-text is an operator, perform it { var is-add?/eax: boolean <- stream-data-equal? curr-text, "+" compare is-add?, 0 break-if-= var _b/eax: int <- pop-int-stack out var b/edx: int <- copy _b var a/eax: int <- pop-int-stack out a <- add b push-int-stack out, a break $evaluate:process-word } { var is-sub?/eax: boolean <- stream-data-equal? curr-text, "-" compare is-sub?, 0 break-if-= var _b/eax: int <- pop-int-stack out var b/edx: int <- copy _b var a/eax: int <- pop-int-stack out a <- subtract b push-int-stack out, a break $evaluate:process-word } { var is-mul?/eax: boolean <- stream-data-equal? curr-text, "*" compare is-mul?, 0 break-if-= var _b/eax: int <- pop-int-stack out var b/edx: int <- copy _b var a/eax: int <- pop-int-stack out a <- multiply b push-int-stack out, a break $evaluate:process-word } # if curr-text is a known function name, call it appropriately { var callee-h: (handle function) var callee-ah/eax: (addr handle function) <- address callee-h find-function defs, curr-text, callee-ah var callee/eax: (addr function) <- lookup *callee-ah compare callee, 0 break-if-= perform-call callee, out, defs break $evaluate:process-word } # otherwise it's an int { var n/eax: int <- parse-decimal-int-from-stream curr-text push-int-stack out, n } } # termination check compare curr, end break-if-= # update var next-word-ah/edx: (addr handle word) <- get curr, next curr <- lookup *next-word-ah # loop } } fn find-function first: (addr handle function), name: (addr stream byte), out: (addr handle function) { var curr/esi: (addr handle function) <- copy first $find-function:loop: { var _f/eax: (addr function) <- lookup *curr var f/ecx: (addr function) <- copy _f compare f, 0 break-if-= var curr-name-ah/eax: (addr handle array byte) <- get f, name var curr-name/eax: (addr array byte) <- lookup *curr-name-ah var done?/eax: boolean <- stream-data-equal? name, curr-name compare done?, 0 # false { break-if-= copy-handle *curr, out break $find-function:loop } curr <- get f, next loop } } fn perform-call _callee: (addr function), caller-stack: (addr int-stack), defs: (addr handle function) { var callee/ecx: (addr function) <- copy _callee # create bindings for args var table-storage: table var table/esi: (addr table) <- address table-storage initialize-table table # var curr-arg-ah/eax: (addr handle word) <- get callee, args var curr-arg/eax: (addr word) <- lookup *curr-arg-ah # var curr-key-storage: (handle array byte) var curr-key/edx: (addr handle array byte) <- address curr-key-storage { compare curr-arg, 0 break-if-= # create binding word-to-string curr-arg, curr-key { var curr-val/eax: int <- pop-int-stack caller-stack bind-int-in-table table, curr-key, curr-val } # var next-arg-ah/edx: (addr handle word) <- get curr-arg, next curr-arg <- lookup *next-arg-ah loop } # obtain body var body-ah/eax: (addr handle line) <- get callee, body var body/eax: (addr line) <- lookup *body-ah # perform call var stack-storage: int-stack var stack/edi: (addr int-stack) <- address stack-storage print-string-to-real-screen "about to enter recursive eval\n" evaluate defs, table, body, 0, stack print-string-to-real-screen "exited recursive eval\n" # stitch result from stack into caller var result/eax: int <- pop-int-stack stack push-int-stack caller-stack, result } # Copy of 'simplify' that just tracks the maximum stack depth needed # Doesn't actually need to simulate the stack, since every word has a predictable effect. fn max-stack-depth first-word: (addr word), final-word: (addr word) -> result/edi: int { var curr-word/eax: (addr word) <- copy first-word var curr-depth/ecx: int <- copy 0 result <- copy 0 $max-stack-depth:loop: { $max-stack-depth:process-word: { # handle operators { var is-add?/eax: boolean <- word-equal? curr-word, "+" compare is-add?, 0 break-if-= curr-depth <- decrement break $max-stack-depth:process-word } { var is-sub?/eax: boolean <- word-equal? curr-word, "-" compare is-sub?, 0 break-if-= curr-depth <- decrement break $max-stack-depth:process-word } { var is-mul?/eax: boolean <- word-equal? curr-word, "*" compare is-mul?, 0 break-if-= curr-depth <- decrement break $max-stack-depth:process-word } # otherwise it's an int (do we need error-checking?) curr-depth <- increment # update max depth if necessary { compare curr-depth, result break-if-<= result <- copy curr-depth } } # if curr-word == final-word break compare curr-word, final-word break-if-= # curr-word = curr-word->next var next-word-ah/edx: (addr handle word) <- get curr-word, next curr-word <- lookup *next-word-ah # loop } }