Introduce pseudo-halt

core/vb.c

@@ -308,6 +308,29 @@ struct VB {
         int      sample; /* Output sample index, period 417 */
     } vsu;
 
+    /* Pseudo-halt */
+    struct {
+        uint32_t address;   /* Monitor address */
+        uint8_t  enabled;   /* Pseudo-halt function is enabled */
+        uint8_t  operation; /* Monitoring operation */
+        uint8_t  step;      /* Number of consecutive matching reads */
+        int      type;      /* Memory access type */
+        int32_t  value;     /* Value read from monitor address */
+
+        /* CPU snapshot */
+        uint32_t adtre;
+        uint32_t chcw;
+        uint32_t eipc;
+        uint32_t eipsw;
+        uint32_t fepc;
+        uint32_t fepsw;
+        uint32_t pc;
+        int32_t  program[31];
+        uint32_t psw;
+        uint32_t sr29;
+        uint32_t sr31;
+    } ph;
+
     /* Other state */
     uint8_t wcr;           /* Wait controller state */
     uint8_t wram[0x10000]; /* System RAM */
@@ -348,6 +371,7 @@ static int32_t SignExtend(int32_t value, int32_t bits) {
 #include "cpu.c"
 #include "vip.c"
 #include "vsu.c"
+#include "pseudo-halt.c"
 
 
 
@@ -451,6 +475,14 @@ VBAPI uint16_t vbGetKeys(VB *sim) {
     return sim->pad.keys;
 }
 
+/* Retrieve a core option value */
+VBAPI int vbGetOption(VB *sim, int key) {
+    switch (key) {
+        case VB_PSEUDO_HALT: return sim->ph.enabled;
+    }
+    return 0;
+}
+
 /* Retrieve the most recent frame image pixels */
 VBAPI void vbGetPixels(VB *sim, void *left, int leftStrideX, int leftStrideY,
     void *right, int rightStrideX, int rightStrideY) {
@@ -553,6 +585,7 @@ VBAPI VB* vbInit(VB *sim) {
     sim->onRead          = NULL;
     sim->onSamples       = NULL;
     sim->onWrite         = NULL;
+    sim->ph.enabled      = 0;
     vbReset(sim);
     return sim;
 }
@@ -583,6 +616,9 @@ VBAPI VB* vbReset(VB *sim) {
     tmrReset(sim);
     vipReset(sim);
     vsuReset(sim);
+
+    /* Pseudo-halt */
+    sim->ph.step = 0;
     return sim;
 }
 
@@ -641,6 +677,23 @@ VBAPI uint16_t vbSetKeys(VB *sim, uint16_t keys) {
     return sim->pad.keys = keys;
 }
 
+/* Specify a new core option value */
+VBAPI int vbSetOption(VB *sim, int key, int value) {
+    switch (key) {
+        case VB_PSEUDO_HALT:
+            sim->ph.enabled = value = !!value;
+            if (!value) {
+                sim->ph.step = 0;
+                if (sim->cpu.operation == CPU_PHALT) {
+                    sim->cpu.operation = CPU_FETCH;
+                    sim->cpu.step      = 0;
+                }
+            }
+            break;
+    }
+    return value;
+}
+
 /* Specify a new value for the program counter */
 VBAPI uint32_t vbSetProgramCounter(VB *sim, uint32_t value) {
     sim->cpu.operation = CPU_FETCH;