1 files changed, 89 insertions, 0 deletions
diff --git a/firmware/zpu/lib/pic.c b/firmware/zpu/lib/pic.c
new file mode 100644
index 000000000..bd627ce6b
--- /dev/null
+++ b/firmware/zpu/lib/pic.c
@@ -0,0 +1,89 @@
+/* -*- c -*- */
+/*
+ * Copyright 2007 Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "pic.h"
+#include "hal_io.h"
+#include "memory_map.h"
+
+
+#define NVECTORS 8
+
+/*
+ * Our secondary interrupt vector.
+ */
+irq_handler_t pic_vector[NVECTORS];
+
+void
+pic_init(void)
+{
+  // uP is level triggered
+
+  pic_regs->mask = ~0;				       // mask all interrupts
+  pic_regs->edge_enable = PIC_ONETIME_INT | PIC_UNDERRUN_INT | PIC_OVERRUN_INT | PIC_PPS_INT;
+  pic_regs->polarity = ~0 & ~PIC_PHY_INT;	       // rising edge
+  pic_regs->pending = ~0;			       // clear all pending ints
+
+  for (int i = 0; i < NVECTORS; i++){
+    pic_vector[i] = pic_nop_handler;
+  }
+}
+
+/*
+ * This magic gets pic_interrupt_handler wired into the
+ * system interrupt handler with the appropriate prologue and
+ * epilogue.
+ */
+//FIXME zpu-gcc does not install interrupt_handler like this
+//void pic_interrupt_handler() __attribute__ ((interrupt_handler));
+
+void pic_interrupt_handler()
+{
+  // pending and not masked interrupts
+  int live = pic_regs->pending & ~pic_regs->mask;
+
+  // FIXME loop while there are interrupts to service.
+  //   That will reduce our overhead.
+
+  // handle the first one set
+  int i;
+  int mask;
+  for (i=0, mask=1; i < NVECTORS; i++, mask <<= 1){
+    if (mask & live){		// handle this one
+      // puthex_nl(i);
+      (*pic_vector[i])(i);
+      pic_regs->pending = mask;	// clear pending interrupt
+      return;
+    }
+  }
+}
+
+void
+pic_register_handler(unsigned irq, irq_handler_t handler)
+{
+  if (irq >= NVECTORS)
+    return;
+  pic_vector[irq] = handler;
+
+  pic_regs->mask &= ~IRQ_TO_MASK(irq);
+}
+
+void
+pic_nop_handler(unsigned irq)
+{
+  // nop
+}