From 412aa1087846d432ddc5bb93c3dcb2acf292010c Mon Sep 17 00:00:00 2001
From: Jonas Hvid <mail@johv.dk>
Date: Tue, 3 Dec 2019 19:54:21 +0100
Subject: [PATCH] Automatically parse integers in INTERPRET

---
 main.asm | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/main.asm b/main.asm
index edcba0a..183be74 100644
--- a/main.asm
+++ b/main.asm
@@ -242,15 +242,55 @@ forth HELLO, 'HELLO'
   dq NEWLINE
   dq EXIT
 
+;; Duplicate a pair of elements.
+forth_asm PAIRDUP, '2DUP'
+  pop rbx
+  pop rax
+  push rax
+  push rbx
+  push rax
+  push rbx
+  next
+
+;; Swap the top two elements on the stack.
+forth_asm SWAP, 'SWAP'
+  pop rax
+  pop rbx
+  push rax
+  push rbx
+  next
+
+;; Remove the top element from the stack.
+forth_asm DROP, 'DROP'
+  add rsp, 8
+  next
+
 ;; The INTERPRET word reads and interprets user input. It's behavior depends on
 ;; the current STATE. It provides special handling for integers. (TODO)
 forth INTERPRET, 'INTERPRET'
+  ;; Read word
   dq READ_WORD
-  dq FIND
+  dq PAIRDUP
+  ;; Stack is (word length word length).
+  dq FIND                       ; Try to find word
+  dq DUP_
+  dq ZBRANCH, 8 * 8             ; Check if word is found
+
+  ;; Word is found, execute it
   dq TCFA
+  ;; Stack is (word length addr)
+  dq SWAP, DROP
+  dq SWAP, DROP
+  ;; Stack is (addr)
   dq EXEC
   dq EXIT
 
+  ;; No word is found, assume it is an integer literal
+  ;; Stack is (word length addr)
+  dq DROP
+  dq PARSE_NUMBER
+  dq EXIT
+
 ;; .U prints the value on the stack as an unsigned integer in hexadecimal.
 forth_asm DOTU, '.U'
   mov [.length], 0
-- 
2.39.2