Don't trace previous instruction multiple times

src/logging.h

@@ -14,17 +14,19 @@
     do {                                               \
         if (logging_level_ >= level) {                 \
             fprintf(dest, type " " __VA_ARGS__);       \
-            extra;                                     \
+            extra                                      \
             fprintf(dest, "\n");                       \
-            after;                                     \
+            after                                      \
         }                                              \
     } while (0);
 
 #define LOG_ERR_(...) LOG_MSG_(stderr, __VA_ARGS__)
 #define LOG_OUT_(...) LOG_MSG_(stdout, __VA_ARGS__)
 
-#define PRINT_ERR_ fprintf(stderr, ": %s", strerror(errno))
-#define EXIT_FAIL_ exit(EXIT_FAILURE)
+#define PRINT_ERR_ fprintf(stderr, ": %s", strerror(errno));
+#define EXIT_FAIL_ exit(EXIT_FAILURE);
+#define NO_EOL_    if (0)
+#define FLUSH_OUT_ fflush(stdout);
 
 #define FATAL_TEXT_ "\x1b[1m\x1b[31m" "fatal:"   "\x1b[0m"
 #define ERROR_TEXT_ "\x1b[1m\x1b[31m" "error:"   "\x1b[0m"
@@ -44,6 +46,7 @@ unsigned logging_level_;
 #define WARN_ERRNO(...)  LOG_ERR_(0,  WARN_TEXT_, PRINT_ERR_, {},         __VA_ARGS__)
 #define DEBUG(...)       LOG_OUT_(1, DEBUG_TEXT_, {},         {},         __VA_ARGS__)
 #define TRACE(...)       LOG_OUT_(2, TRACE_TEXT_, {},         {},         __VA_ARGS__)
+#define TRACE_NOEOL(...) LOG_OUT_(2, TRACE_TEXT_, NO_EOL_,    FLUSH_OUT_, __VA_ARGS__)
 
 #define SET_LOG_LEVEL(level) logging_level_ = (level);
 #define DEBUG_LEVEL (logging_level_ >= 1)

src/z80.c

@@ -82,6 +82,10 @@ void z80_power(Z80 *z80)
 
     z80->except = false;
     z80->pending_cycles = 0;
+
+    z80->trace.fresh = true;
+    z80->trace.last_addr = 0;
+    z80->trace.counter = 0;
 }
 
 /*
@@ -182,8 +186,19 @@ static inline void increment_refresh_counter(Z80 *z80)
     @TRACE_LEVEL
     Trace the instruction about to be executed by the CPU.
 */
-static inline void trace_instruction(const Z80 *z80)
+static inline void trace_instruction(Z80 *z80)
 {
+    if (z80->regfile.pc == z80->trace.last_addr && !z80->trace.fresh) {
+        z80->trace.counter++;
+        if (!(z80->trace.counter % (1 << 14)))
+            TRACE_NOEOL("repeat last: %llu times\r", z80->trace.counter);
+        return;
+    }
+    if (z80->trace.fresh)
+        z80->trace.fresh = false;
+    z80->trace.last_addr = z80->regfile.pc;
+    z80->trace.counter = 0;
+
     uint32_t quad = mmu_read_quad(z80->mmu, z80->regfile.pc);
     uint8_t bytes[4] = {quad, quad >> 8, quad >> 16, quad >> 24};
     DisasInstr *instr = disassemble_instruction(bytes);

src/z80.h

@@ -23,11 +23,18 @@ typedef struct {
 } Z80RegFile;
 
 typedef struct {
+    bool fresh;
+    uint16_t last_addr;
+    uint64_t counter;
+} Z80TraceInfo;
+
+typedef struct {
     Z80RegFile regfile;
     MMU *mmu;
     bool except;
     uint8_t exc_code, exc_data;
     double pending_cycles;
+    Z80TraceInfo trace;
 } Z80;
 
 /* Functions */