From: Jonas Hvid <mail@johv.dk>
Date: Sun, 8 Dec 2019 17:32:21 +0000 (+0100)
Subject: Add space for immediate flag
X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=89a6a52d6128a4f9ac3c7aa26fc0df111e4160db;p=rrq%2Fjonasforth.git

Add space for immediate flag

We don't actually use this for anything yet.
---

diff --git a/impl.asm b/impl.asm
index f8093d0..5736469 100644
--- a/impl.asm
+++ b/impl.asm
@@ -15,12 +15,12 @@ segment readable executable
 find:
   ;; RSI contains the entry we are currently looking at
 .loop:
-  movzx rcx, byte [rsi + 8]     ; Length of word being looked at
+  movzx rcx, byte [rsi + 16]    ; Length of word being looked at
   cmp rcx, [.search_length]
   jne .next    ; If the words don't have the same length, we have the wrong word
 
   ;; Otherwise, we need to compare strings
-  lea rdx, [rsi + 8 + 1]        ; Location of character being compared in entry
+  lea rdx, [rsi + 16 + 1]       ; Location of character being compared in entry
   mov rdi, [.search_buffer]     ; Location of character being compared in search buffer
 .compare_char:
   mov al, [rdx]
diff --git a/main.asm b/main.asm
index d0c4391..8133cdc 100644
--- a/main.asm
+++ b/main.asm
@@ -32,11 +32,12 @@ macro popr x {
 ;;
 ;; This macro also defines a label LABEL_entry.
 initial_latest_entry = 0
-macro header label, name {
+macro header label, name, immediate {
   local .string_end
 
 label#_entry:
   dq initial_latest_entry
+  dq 0
   db .string_end - ($ + 1)
   db name
   .string_end:
@@ -46,16 +47,16 @@ initial_latest_entry = label#_entry
 }
 
 ;; Define a Forth word that is implemented in assembly. See 'header' for details.
-macro forth_asm label, name {
-  header label, name
+macro forth_asm label, name, immediate {
+  header label, name, immediate
   dq .start
 .start:
 }
 
 ;; Define a Forth word that is implemented in Forth. (The body will be a list of
 ;; 'dq' statements.)
-macro forth label, name {
-  header label, name
+macro forth label, name, immediate {
+  header label, name, immediate
   dq DOCOL
 }
 
@@ -117,7 +118,7 @@ forth_asm FIND, 'FIND'
 ;; entry.
 forth_asm TCFA, '>CFA'
   pop rax
-  add rax, 8                    ; [rax] = length of name
+  add rax, 16                   ; [rax] = length of name
   movzx rbx, byte [rax]
   inc rax
   add rax, rbx                  ; [rax] = codeword
@@ -453,6 +454,10 @@ forth_asm CREATE, 'CREATE'
   mov [rdi], rax                ; Insert link to previous entry
   mov [latest_entry], rdi       ; Update LATEST to point to this word
 
+  add rdi, 8
+  mov rax, 0
+  mov [rdi], rax                ; Set immediate flag
+
   add rdi, 8
   mov [rdi], rcx                ; Insert length
 
@@ -469,6 +474,21 @@ forth_asm CREATE, 'CREATE'
 
   next
 
+;; Mark the last added word as immediate.
+forth IMMEDIATE, 'IMMEDIATE', 1
+  dq LIT, 1
+  dq LATEST, GET
+  dq LIT, 8, PLUS
+  dq PUT
+  dq EXIT
+
+;; Return 0 if the given word is not immediate.
+forth IS_IMMEDIATE, 'IMMEDIATE?'
+  dq FIND
+  dq LIT, 8, PLUS
+  dq GET
+  dq EXIT
+
 forth MAIN, 'MAIN'
   dq HELLO
   dq INTERPRET