-;; vim: syntax=fasm
-
-;; We need some basic words to be available before we can implement the actual
-;; interpreter. For this reason we need to write some words in assembly, even
-;; though they depend only on other Forth words. Such words are defined in this
-;; file.
+;; We need some basic words to be available before we can implement
+;; the actual interpreter. For this reason we need to write some words
+;; in assembly, even though they depend only on other Forth words.
+;; Such words are defined in this file.
;;
-;; With these words, we can finally defined INTERPRET, and from there we'll load
-;; everything else from an external file.
+;; With these words, we can finally defined INTERPRET, and from there
+;; we'll load everything else from an external file.
;;
-;; This file is included from main.asm; see that file for more information.
+;; This file is included from main.asm; see that file for more
+;; information.
-;; Define a Forth word that is implemented in Forth. (The body will be a list of
-;; 'dq' statements.)
+;; Define a Forth word that is implemented in Forth. (The body will be
+;; a list of 'dq' statements.)
macro forth label, name, immediate {
header label, name, immediate
dq DOCOL
}
forth COMMA, ','
- dq HERE, GET, PUT ; Set the memory at the address pointed to by HERE
- dq HERE, GET, LIT, 8, PLUS ; Calculate new address for HERE to point to
- dq HERE, PUT ; Update HERE to point to the new address
+ dq HERE, GET, PUT ; Set the memory at the address pointed to by HERE
+ dq HERE, GET, LIT, 8, PLUS ; Calculate new address for HERE to point to
+ dq HERE, PUT ; Update HERE to point to the new address
dq EXIT
;; Mark the last added word as immediate.
dq LIT, 1, STATE, PUT_BYTE
dq EXIT
-;; INTERPRET-WORD expects a word as a (buffer, length) pair on the stack. It
-;; interprets and executes the word. It's behavior depends on the current STATE.
-;; It provides special handling for integers.
+;; INTERPRET-WORD expects a word as a (buffer, length) pair on the
+;; stack. It interprets and executes the word. It's behavior depends
+;; on the current STATE. It provides special handling for integers.
forth INTERPRET_WORD, 'INTERPRET-WORD'
dq PAIRDUP
;; Stack is (word length word length).
;; - Word is found -
- dq STATE, GET, ZBRANCH, 8 * 11 ; Check whether we are in compilation or immediate mode
+ dq STATE, GET, ZBRANCH, 8 * 11 ; Check whether we are in compilation
+ ; or immediate mode
;; (Word found, compilation mode)
- dq DUP_, IS_IMMEDIATE, NOT_, ZBRANCH, 8 * 6 ; If the word is immediate, continue as we would in immediate mode
+ dq DUP_, IS_IMMEDIATE, NOT_, ZBRANCH, 8 * 6 ; If the word is
+ ; immediate, continue as we would in
+ ; immediate mode
;; Otherwise, we want to compile this word
dq TCFA
dq DROP
dq PARSE_NUMBER
- dq STATE, GET, ZBRANCH, 8 * 5 ; Check whether we are in compilation or immediate mode
+ dq STATE, GET, ZBRANCH, 8 * 5 ; Check whether we are in compilation
+ ; or immediate mode
;; (Number, compilation mode)
dq LIT, LIT, COMMA
;; (Number, immediate mode)
dq EXIT
-;; The INTERPRET word reads and interprets a single word from the user.
+;; The INTERPRET word reads and interprets a single word from the
+;; user.
forth INTERPRET, 'INTERPRET'
dq READ_WORD
dq INTERPRET_WORD
dq EXIT
-;; INTERPRET_STRING is a variant of INTERPRET that reads from a string instead
-;; of from the user. It takes a string as a (buffer, length) pair on the stack
-;; and interprets the entire string, even if the string has more than one word.
+;; INTERPRET_STRING is a variant of INTERPRET that reads from a string
+;; instead of from the user. It takes a string as a (buffer, length)
+;; pair on the stack and interprets the entire string, even if the
+;; string has more than one word.
forth INTERPRET_STRING, 'INTERPRET-STRING'
dq INPUT_LENGTH, PUT
dq INPUT_BUFFER, PUT
;; Check if the buffer is-non-empty
- ;; [TODO] This probably won't work for strings with whitespace at the end.
+ ;; [TODO] This probably won't work for strings with whitespace at
+ ;; the end.
dq INPUT_LENGTH, GET
dq ZBRANCH, 8 * 5 ; to EXIT