emux64: cpu: Add emulation of MUL instruction

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/emux64/src/cpu/cpu_cycle.c b/emux64/src/cpu/cpu_cycle.c
index 663b300..9f30788 100644
--- a/emux64/src/cpu/cpu_cycle.c
+++ b/emux64/src/cpu/cpu_cycle.c
@@ -222,6 +222,21 @@ cpu_do_sub(struct osmx_core *core)
     return 0;
 }
 
+static int
+cpu_do_mul(struct osmx_core *core)
+{
+    struct arithop ops;
+    int error;
+
+    error = cpu_arithop(core, &ops);
+    if (error < 0) {
+        return error;
+    }
+
+    core->xn[ops.dest_reg] = ops.op1 * ops.op2;
+    return 0;
+}
+
 int
 cpu_run(struct osmx_core *core)
 {
@@ -261,6 +276,12 @@ cpu_run(struct osmx_core *core)
                 continue;
             }
             break;
+        case OP_MUL:
+            if (cpu_do_mul(core) < 0) {
+                core->run = false;
+                continue;
+            }
+            break;
         case OP_NOP:
             break;
         default: