cpm80: Simplify emulator speed setting

src/arch/cpm80/cpm80.c

···
  *****************************************************************************/
 
 /*****************************************************************************
- * File name:   src/arch/sim8080/sim8080.c                                   *
+ * File name:   src/arch/cpm80/cpm80.c                                       *
  * Created:     2012-11-28 by Hampa Hug <[e-mail]>                     *
- * Copyright:   (C) 2012-2020 Hampa Hug <[e-mail]>                     *
+ * Copyright:   (C) 2012-2021 Hampa Hug <[e-mail]>                     *
  *****************************************************************************/
 
 /*****************************************************************************
···
 	if (ini_get_uint32 (sct, "clock", &clock, 0)) {
 		ini_get_uint16 (sct, "speed", &speed, 1);
 
-		if (speed <= 4) {
-			clock = 1000000UL * speed;
-		}
-		else {
-			clock = 8000000UL * (speed - 4);
-		}
+		clock = 1000000UL * speed;
 
 		sim->speed = speed;
 	}
···
 
 void c80_set_speed (cpm80_t *sim, unsigned speed)
 {
-	unsigned long clk;
-
 	sim->speed = speed;
 
-	if (speed <= 4) {
-		clk = 1000000UL * speed;
-	}
-	else {
-		clk = 8000000UL * (speed - 4);
-	}
-
-	c80_set_clock (sim, clk);
+	c80_set_clock (sim, 1000000UL * speed);
 }
 
 static

src/arch/cpm80/msg.c

···
 /*****************************************************************************
  * File name:   src/arch/cpm80/msg.c                                         *
  * Created:     2012-11-30 by Hampa Hug <[e-mail]>                     *
- * Copyright:   (C) 2012-2020 Hampa Hug <[e-mail]>                     *
+ * Copyright:   (C) 2012-2021 Hampa Hug <[e-mail]>                     *
  *****************************************************************************/
 
 /*****************************************************************************
···
 		return (1);
 	}
 
+	if (v > 4) {
+		v = 8 * (v - 4);
+	}
+
 	c80_set_speed (sim, v);
+
+	return (0);
+}
+
+static
+int c80_set_msg_emu_cpu_speed_double (cpm80_t *sim, const char *msg, const char *val)
+{
+	c80_set_speed (sim, 2 * sim->speed);
+
+	return (0);
+}
+
+static
+int c80_set_msg_emu_cpu_speed_half (cpm80_t *sim, const char *msg, const char *val)
+{
+	if (sim->speed > 1) {
+		c80_set_speed (sim, sim->speed / 2);
+	}
 
 	return (0);
 }
···
 	{ "emu.con.write", c80_set_msg_emu_con_write },
 	{ "emu.cpu.model", c80_set_msg_emu_cpu_model },
 	{ "emu.cpu.speed", c80_set_msg_emu_cpu_speed },
+	{ "emu.cpu.speed.double", c80_set_msg_emu_cpu_speed_double },
+	{ "emu.cpu.speed.half", c80_set_msg_emu_cpu_speed_half },
 	{ "emu.cpu.speed.step", c80_set_msg_emu_cpu_speed_step },
 	{ "emu.disk.commit", c80_set_msg_emu_disk_commit },
 	{ "emu.disk.eject", c80_set_msg_emu_disk_eject },