3b2: WE32106 Math Acceleration Unit (MAU)

This change adds support for the WE32106 Math Acceleration Unit (MAU).
The WE32106 is an IEEE-754 1985 compatible floating point math
acceleration unit that was an optional component on the 3B2/310 and
3B2/400.

The MAU is implemented using software floating point routines.  As
always, there may be bugs, but the MAU currently passes extensive
floating point tests with exactly the same results as a real 3B2/400
equipped with a physical MAU, so I hope these are few.

3B2/3b2_sys.c

@@ -38,6 +38,7 @@
 #include "3b2_ctc.h"
 #include "3b2_ports.h"
 #include "3b2_ni.h"
+#include "3b2_mau.h"
 #include "3b2_sysdev.h"
 
 char sim_name[] = "AT&T 3B2 Model 400";
@@ -53,6 +54,7 @@ extern instr *cpu_instr;
 DEVICE *sim_devices[] = {
     &cpu_dev,
     &mmu_dev,
+    &mau_dev,
     &timer_dev,
     &tod_dev,
     &nvram_dev,
@@ -86,6 +88,7 @@ const char *sim_stop_messages[] = {
 void full_reset()
 {
     cpu_reset(&cpu_dev);
+    mau_reset(&mau_dev);
     tti_reset(&tti_dev);
     contty_reset(&contty_dev);
     iu_timer_reset(&iu_timer_dev);