adding support for verilator-driven AFU driver: vlsim

driver/opae/vlsim/ram.h

@@ -0,0 +1,64 @@
+#pragma once
+
+#include <stdio.h>
+#include <stdint.h>
+
+class RAM {
+private:
+
+  mutable uint8_t *mem_[(1 << 12)];      
+
+  uint8_t *get(uint32_t address) const {
+    uint32_t block_addr   = address >> 20;
+    uint32_t block_offset = address & 0x000FFFFF;
+    if (mem_[block_addr] == NULL) {
+      mem_[block_addr] = new uint8_t[(1 << 20)];
+    }
+    return mem_[block_addr] + block_offset;
+  }
+
+public:
+
+  RAM() {
+    for (uint32_t i = 0; i < (1 << 12); i++) {
+      mem_[i] = NULL;
+    }
+  }
+
+  ~RAM() {
+    this->clear();
+  }
+
+  size_t size() const {
+    return (1ull << 32);
+  }
+
+  void clear() {
+    for (uint32_t i = 0; i < (1 << 12); i++) {
+      if (mem_[i]) {
+        delete mem_[i];
+        mem_[i] = NULL;
+      }
+    }
+  }
+
+  void read(uint32_t address, uint32_t length, uint8_t *data) const {
+    for (unsigned i = 0; i < length; i++) {
+      data[i] = *this->get(address + i);
+    }
+  }
+
+  void write(uint32_t address, uint32_t length, const uint8_t *data) {
+    for (unsigned i = 0; i < length; i++) {
+      *this->get(address + i) = data[i];
+    }
+  }
+
+  uint8_t& operator[](uint32_t address) {
+    return *get(address);
+  }
+
+  const uint8_t& operator[](uint32_t address) const {
+    return *get(address);
+  }
+};