From ab27a5301400224e67cb3698a98f6912254f0676 Mon Sep 17 00:00:00 2001
From: Seth Morabito <web@loomcom.com>
Date: Sun, 11 Aug 2019 22:47:00 -0700
Subject: [PATCH] 3b2: Fix STRCPY instruction

STRCPY must increment both source and destination pointers (R0 and R1).
---
 3B2/3b2_cpu.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/3B2/3b2_cpu.c b/3B2/3b2_cpu.c
index 08841ca4..e7be4c13 100644
--- a/3B2/3b2_cpu.c
+++ b/3B2/3b2_cpu.c
@@ -3018,14 +3018,11 @@ t_stat sim_instr(void)
             break;
         case STRCPY:
             a = 0;
-            b = 0;
-
-            do {
-                b = read_b(R[0] + a, ACC_AF);
-                write_b(R[1] + a, (uint8) b);
-                a++;
-            } while (b != '\0');
-
+            while ((a = read_b(R[0], ACC_AF)) != '\0') {
+                write_b(R[1], (uint8) a);
+                R[0]++;
+                R[1]++;
+            }
             break;
         case TSTW:
             a = cpu_read_op(src1);