+/* measure f_cpu */
+void do_msg_m_fcpu(uint8_t subf, int len UNUSED, uint8_t * msg)
+{
+ uint32_t freq;
+ uint8_t eimsk_save;
+
+ /* Save state and disable INT5/INT6 */
+ ATOMIC_BLOCK(ATOMIC_FORCEON) {
+ eimsk_save = EIMSK;
+ EIMSK &= ~_BV(INT6);
+ EIMSK &= ~_BV(INT5);
+ }
+ EIFR = _BV(INTF5); /* Reset pending int */
+ z80_bus_cmd(Request);
+ z80_write(0x3f, 0xff);
+ z80_bus_cmd(Release);
+
+ freq = z80_measure_phi(*msg);
+
+ z80_bus_cmd(Request);
+ z80_write(0x3f, 0xff);
+ z80_bus_cmd(Release);
+
+ /* Restore INT5/INT6 */
+ ATOMIC_BLOCK(ATOMIC_FORCEON) {
+ if ((eimsk_save & _BV(INT5)) != 0)
+ EIMSK |= _BV(INT5);
+ if ((eimsk_save & _BV(INT6)) != 0)
+ EIMSK |= _BV(INT6);
+ /* Reset pending int */
+ EIFR = _BV(INTF5);
+ EIFR = _BV(INTF6);
+ }
+
+ msg_xmit(4, subf, sizeof(freq), (uint8_t *) &freq);
+}
+
+/* ---------------------------------------------------------------------------*/
+