From 9cb338f83e5e1ccd4cf597538d1592ea21881e96 Mon Sep 17 00:00:00 2001
From: Maurizio Porrato <maurizio.porrato@gmail.com>
Date: Fri, 24 Apr 2020 07:41:14 +0100
Subject: [PATCH] Fix execution of instructions with two literals

---
 dsim.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/dsim.c b/dsim.c
index 335b9f0..c8333f1 100644
--- a/dsim.c
+++ b/dsim.c
@@ -15,7 +15,7 @@
 uint16_t ram[0x10000];
 uint16_t ra, rb, rc, rx, ry, rz, ri, rj;
 uint16_t rpc, rsp, rex, ria;
-uint16_t lit; /* temporary storage for literal operands */
+uint16_t lit_a, lit_b; /* temporary storage for literal operands */
 
 bool skip_next;
 uint64_t ticks;
@@ -78,6 +78,10 @@ void shutdown()
 
 uint16_t *val(int operand, bool is_a)
 {
+    uint16_t *lit;
+
+    lit = (is_a ? &lit_a : &lit_b);
+
     switch (operand) {
     case 0x00:
         return &ra;
@@ -153,11 +157,11 @@ uint16_t *val(int operand, bool is_a)
         return &ram[ram[rpc++]];
     case 0x1f:
         ticks++;
-        lit = ram[rpc++];
-        return &lit;
+        *lit = ram[rpc++];
+        return lit;
     default:
-        lit = operand - 0x21;
-        return &lit;
+        *lit = operand - 0x21;
+        return lit;
     }
 }