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3 Copyright (C) 1998-2016 Free Software Foundation, Inc.
4 Contributed by Cygnus Solutions.
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
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28 tx3904cpu - tx3904 cpu virtual device
34 Implements the external tx3904 functionality. This includes the
35 delivery of of interrupts generated from other devices and the
36 handling of device specific registers.
54 Deliver a non-maskable interrupt to the processor.
59 Deliver a maskable interrupt of given level, corresponding to
60 IP[5:0], to processor.
67 When delivering an interrupt, this code assumes that there is only
68 one processor (number 0).
70 This code does not attempt to be efficient at handling pending
71 interrupts. It simply schedules the interrupt delivery handler
72 every instruction cycle until all pending interrupts go away. An
73 alternative implementation might modify instructions that change
74 the PSW and have them check to see if the change makes an interrupt
82 /* Pending interrupts for delivery by event handler */
83 int pending_reset, pending_nmi, pending_level;
84 struct hw_event* event;
98 static const struct hw_port_descriptor tx3904cpu_ports[] = {
100 /* interrupt inputs */
101 { "reset", RESET_PORT, 0, input_port, },
102 { "nmi", NMI_PORT, 0, input_port, },
103 { "level", LEVEL_PORT, 0, input_port, },
109 /* Finish off the partially created hw device. Attach our local
110 callbacks. Wire up our port names etc */
112 static hw_port_event_method tx3904cpu_port_event;
117 tx3904cpu_finish (struct hw *me)
119 struct tx3904cpu *controller;
121 controller = HW_ZALLOC (me, struct tx3904cpu);
122 set_hw_data (me, controller);
123 set_hw_ports (me, tx3904cpu_ports);
124 set_hw_port_event (me, tx3904cpu_port_event);
126 /* Initialize the pending interrupt flags */
127 controller->pending_level = 0;
128 controller->pending_reset = 0;
129 controller->pending_nmi = 0;
130 controller->event = NULL;
135 /* An event arrives on an interrupt port */
138 deliver_tx3904cpu_interrupt (struct hw *me,
141 struct tx3904cpu *controller = hw_data (me);
142 SIM_DESC sd = hw_system (me);
143 sim_cpu *cpu = STATE_CPU (sd, 0); /* NB: fix CPU 0. */
144 address_word cia = CPU_PC_GET (cpu);
147 #define SD current_state
149 if (controller->pending_reset)
151 controller->pending_reset = 0;
152 HW_TRACE ((me, "reset pc=0x%08lx", (long) CPU_PC_GET (cpu)));
153 SignalExceptionNMIReset();
155 else if (controller->pending_nmi)
157 controller->pending_nmi = 0;
158 HW_TRACE ((me, "nmi pc=0x%08lx", (long) CPU_PC_GET (cpu)));
159 SignalExceptionNMIReset();
161 else if (controller->pending_level)
163 HW_TRACE ((me, "interrupt level=%d pc=0x%08lx sr=0x%08lx",
164 controller->pending_level,
165 (long) CPU_PC_GET (cpu), (long) SR));
167 /* Clear CAUSE register. It may stay this way if the interrupt
168 was cleared with a negative pending_level. */
169 CAUSE &= ~ (cause_IP_mask << cause_IP_shift);
171 if(controller->pending_level > 0) /* interrupt set */
173 /* set hardware-interrupt subfields of CAUSE register */
174 CAUSE |= (controller->pending_level & cause_IP_mask) << cause_IP_shift;
176 /* check for enabled / unmasked interrupts */
177 if((SR & status_IEc) &&
178 (controller->pending_level & ((SR >> status_IM_shift) & status_IM_mask)))
180 controller->pending_level = 0;
181 SignalExceptionInterrupt(0 /* dummy value */);
185 /* reschedule soon */
186 if(controller->event != NULL)
187 hw_event_queue_deschedule(me, controller->event);
189 hw_event_queue_schedule (me, 1, deliver_tx3904cpu_interrupt, NULL);
191 } /* interrupt set */
194 #undef SD current_state
199 tx3904cpu_port_event (struct hw *me,
205 struct tx3904cpu *controller = hw_data (me);
210 controller->pending_reset = 1;
211 HW_TRACE ((me, "port-in reset"));
215 controller->pending_nmi = 1;
216 HW_TRACE ((me, "port-in nmi"));
220 /* level == 0 means that the interrupt was cleared */
222 controller->pending_level = -1; /* signal end of interrupt */
224 controller->pending_level = level;
225 HW_TRACE ((me, "port-in level=%d", level));
229 hw_abort (me, "bad switch");
233 /* Schedule an event to be delivered immediately after current
235 if(controller->event != NULL)
236 hw_event_queue_deschedule(me, controller->event);
238 hw_event_queue_schedule (me, 0, deliver_tx3904cpu_interrupt, NULL);
242 const struct hw_descriptor dv_tx3904cpu_descriptor[] = {
243 { "tx3904cpu", tx3904cpu_finish, },