Impove accurate DSK/Hawk

Can now boot WIPL and LOAD again.
Might even be getting slightly futher, because I added interrupts.

Author: phire

centurion.c

@@ -817,15 +817,18 @@ int main(int argc, char *argv[])
 		if (cpu6_halted())
 			halt_system();
 		/* Service DMA */
-		if (hawk_dma == 1) {
-			if (dma_read_cycle(hawk_read_next()))
-				hawk_dma_done();
-		}
-		if (hawk_dma == 2) {
-			if (dma_write_active())
-				hawk_write_next(dma_write_cycle());
-			else
-				hawk_dma_done();
+		if (hawk_dma) {
+			while(dma_write_active()) {
+				// Advance time to next scheduler event
+				int64_t next = scheduler_next();
+				if (next == -1) {
+					fprintf(stderr, "DMA stalled\n");
+					exit(-1);
+				}
+				cpu_timestamp_ns = next;
+				run_scheduler(cpu_timestamp_ns, trace & TRACE_SCHEDULER);
+			}
+			hawk_dma_done();
 		}
 		/* Floppy controller command host to controller */
 		if (fd_dma == 1) {

cpu6.c

@@ -102,6 +102,17 @@ uint16_t cpu6_dma_count(void) {
 	return ~dma_count;
 }
 
+void cpu6_dma_write(uint8_t byte) {
+	/* DMA is done when it incs to 0 */
+	if (dma_enable == 0 || ++dma_count == 0) {
+		dma_enable = 0;
+		return;
+	}
+	if (dma_enable) {
+		mem_write8(dma_addr++, byte);
+	}
+}
+
 /*
  *	When packed into C, the flags live in the upper 4 bits of the low byte
  */

cpu6.h

@@ -50,3 +50,5 @@ extern void cpu_assert_irq(unsigned ipl);
 extern void cpu_deassert_irq(unsigned ipl);
 extern void advance_time(uint64_t nanoseconds);
 extern uint16_t cpu6_dma_count(void);
+extern void cpu6_dma_write(uint8_t);
+extern uint8_t cpu6_dma_read(void);