Support more flexible main memory allocation

1 files changed, 54 insertions, 4 deletions

diff --git a/spike_main/spike.cc b/spike_main/spike.cc
index dde6f5a..80c5fa6 100644
--- a/spike_main/spike.cc
+++ b/spike_main/spike.cc
@@ -18,7 +18,9 @@ static void help()
   fprintf(stderr, "usage: spike [host options] <target program> [target options]\n");
   fprintf(stderr, "Host Options:\n");
   fprintf(stderr, "  -p<n>                 Simulate <n> processors [default 1]\n");
-  fprintf(stderr, "  -m<n>                 Provide <n> MiB of target memory [default 4096]\n");
+  fprintf(stderr, "  -m<n>                 Provide <n> MiB of target memory [default 2048]\n");
+  fprintf(stderr, "  -m<a:m,b:n,...>       Provide memory regions of size m and n bytes\n");
+  fprintf(stderr, "                          at base addresses a and b (with 4 KiB alignment)\n");
   fprintf(stderr, "  -d                    Interactive debug mode\n");
   fprintf(stderr, "  -g                    Track histogram of PCs\n");
   fprintf(stderr, "  -l                    Generate a log of execution\n");
@@ -35,6 +37,51 @@ static void help()
   exit(1);
 }
 
+static std::vector<std::pair<reg_t, mem_t*>> make_mems(const char* arg)
+{
+  // handle legacy mem argument
+  char* p;
+  auto mb = strtoull(arg, &p, 0);
+  if (*p == 0) {
+    reg_t size = reg_t(mb) << 20;
+    return std::vector<std::pair<reg_t, mem_t*>>(1, std::make_pair(reg_t(DRAM_BASE), new mem_t(size)));
+  }
+
+  // handle base/size tuples
+  std::vector<std::pair<reg_t, mem_t*>> res;
+  while (true) {
+    auto base = strtoull(arg, &p, 0);
+    if (!*p || *p != ':')
+      help();
+    auto size = strtoull(p + 1, &p, 0);
+    if ((size | base) % PGSIZE != 0)
+      help();
+    res.push_back(std::make_pair(reg_t(base), new mem_t(size)));
+    if (!*p)
+      break;
+    if (*p != ',')
+      help();
+    arg = p + 1;
+  }
+  return res;
+#if 0
+  // allocate target machine's memory, shrinking it as necessary
+  // until the allocation succeeds
+  size_t memsz0 = (size_t)mem_mb << 20;
+  size_t quantum = 1L << 20;
+  if (memsz0 == 0)
+    memsz0 = (size_t)2048 << 20;
+
+  memsz = memsz0;
+  while ((mem = (char*)calloc(1, memsz)) == NULL)
+    memsz = (size_t)(memsz*0.9)/quantum*quantum;
+
+  if (memsz != memsz0)
+    fprintf(stderr, "warning: only got %zu bytes of target mem (wanted %zu)\n",
+            memsz, memsz0);
+#endif
+}
+
 int main(int argc, char** argv)
 {
   bool debug = false;
@@ -43,7 +90,7 @@ int main(int argc, char** argv)
   bool log = false;
   bool dump_dts = false;
   size_t nprocs = 1;
-  size_t mem_mb = 0;
+  std::vector<std::pair<reg_t, mem_t*>> mems;
   std::unique_ptr<icache_sim_t> ic;
   std::unique_ptr<dcache_sim_t> dc;
   std::unique_ptr<cache_sim_t> l2;
@@ -58,7 +105,7 @@ int main(int argc, char** argv)
   parser.option('g', 0, 0, [&](const char* s){histogram = true;});
   parser.option('l', 0, 0, [&](const char* s){log = true;});
   parser.option('p', 0, 1, [&](const char* s){nprocs = atoi(s);});
-  parser.option('m', 0, 1, [&](const char* s){mem_mb = atoi(s);});
+  parser.option('m', 0, 1, [&](const char* s){mems = make_mems(s);});
   // I wanted to use --halted, but for some reason that doesn't work.
   parser.option('H', 0, 0, [&](const char* s){halted = true;});
   parser.option(0, "gdb-port", 1, [&](const char* s){gdb_port = atoi(s);});
@@ -78,7 +125,10 @@ int main(int argc, char** argv)
 
   auto argv1 = parser.parse(argv);
   std::vector<std::string> htif_args(argv1, (const char*const*)argv + argc);
-  sim_t s(isa, nprocs, mem_mb, halted, htif_args);
+  if (mems.empty())
+    mems = make_mems("2048");
+
+  sim_t s(isa, nprocs, halted, mems, htif_args);
   std::unique_ptr<gdbserver_t> gdbserver;
   if (gdb_port) {
     gdbserver = std::unique_ptr<gdbserver_t>(new gdbserver_t(gdb_port, &s));