From a13f56016d10edd1bdc76cadbb0f5f7fd11e0970 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Mon, 1 May 2023 22:13:54 +0100
Subject: Added equ to assembler

To define constants.
---
 example.asm |  8 ++++++--
 tr8as.c     | 35 ++++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/example.asm b/example.asm
index 7d69611..694501c 100644
--- a/example.asm
+++ b/example.asm
@@ -3,10 +3,14 @@
 ;
 .org 0
 
+; address of the frame interrupt vector
+.equ INT_VECT 0xff00
+
     ; setup an int handler so we
     ; can use the frame int to sync
-    ld a, 0xff
-    ld x, 0
+    ld a, >INT_VECT
+    ld x, <INT_VECT
+
     ld b, <int_handler
     ld [a : x], b
     inc x
diff --git a/tr8as.c b/tr8as.c
index e450288..6c9bd27 100644
--- a/tr8as.c
+++ b/tr8as.c
@@ -232,6 +232,15 @@ static uint8_t new_label(As *as, char *word)
     return 1;
 }
 
+static uint8_t new_label_imm(As *as, char *word, uint16_t imm)
+{
+    if (!new_label(as, word))
+        return 1;
+
+    as->labels[as->lcnt - 1].addr = imm;
+    return 1;
+}
+
 static uint8_t new_ref(As *as, char *word, uint16_t mask, uint16_t addr)
 {
     Mod mod = ModNone;
@@ -340,6 +349,30 @@ static uint8_t parse_org(As *as, char *c)
     return 1;
 }
 
+static uint8_t parse_equ(As *as, char *c)
+{
+    char label[MAX_ID + 1];
+    char word[MAX_ID + 1];
+    char *pt;
+    uint8_t wlen;
+    uint16_t imm;
+
+    /* .equ label imm */
+
+    pt = next_word(c, label, &wlen);
+    if (wlen == 0)
+        return error_l("Syntax error", &as->loc, "expected label");
+
+    next_word(pt, word, &wlen);
+    if (wlen == 0)
+        return error_l("Syntax error", &as->loc, "expected immediate");
+
+    if (next_imm(word, &imm))
+        return error_l("Syntax error", &as->loc, word);
+
+    return new_label_imm(as, label, imm);
+}
+
 static uint8_t parse_db(As *as, char *c)
 {
     char word[MAX_ID + 1];
@@ -1213,6 +1246,7 @@ static uint8_t parse_ld(As *as, char *c)
 
 static InstParse insts[] = {
     { ".org", parse_org },
+    { ".equ", parse_equ },
     { ".db", parse_db },
     { ".dw", parse_dw },
     { "halt", parse_halt },
@@ -1287,7 +1321,6 @@ static uint8_t parse(As *as, char *c)
         for (i = 0; insts[i].parse; i++)
             if (!strcasecmp(insts[i].id, word))
                 return insts[i].parse(as, pt);
-        printf("NOPE %s\n", word);
 
         return error_l("Parse error", &as->loc, word);
     }
-- 
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