Oki Dr.63514, User Manual, Page: 46 / 101

Chapter 2. Functions
2-25
2.5 Real-time Tracing
Real-time tracing stores the current instruction address, the contents of ACC and other registers, flag
states, etc. for post mortem analysis of real-time emulation.
The emulator uses the 13-bit trace pointer to keep track of the location of the next entry to be written
within its 8192-entry trace table. When the trace pointer reaches that number, it recycles, overwriting the
oldest entry first.
0
Trace data
1
2
3
4
8190
8191
Trace memory
Trace
signal
(13-bit counter)
Trace pointer
(Overflow signal) Trace
memory full
break request
Trace enable bits
Trace control circuit
Program
counter
output
Figure 2-7 Real-Time Tracing
For each code memory address, the emulator provides a trace enable bit for use in limiting tracing to
specific addresses.
0000H
0001H
0002H
0003H
0004H
Trace enable bits
Address specified by
program counter (PC)
0FFFDH
0FFFEH
0FFFFH
To trace control circuit
Code memory
Figure 2-8 Trace Enable Bits