From 6a571f710ee7f8a6a107176ac5b7dd8a9f14cf0b Mon Sep 17 00:00:00 2001
From: Andrew Waterman <andrew@sifive.com>
Date: Mon, 13 Apr 2020 19:00:56 -0700
Subject: Handle misaligned memories by aligning them, rather than erroring

Resolves #442
---
 spike_main/spike.cc | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/spike_main/spike.cc b/spike_main/spike.cc
index 31c0cd7..9056f31 100644
--- a/spike_main/spike.cc
+++ b/spike_main/spike.cc
@@ -112,8 +112,23 @@ static std::vector<std::pair<reg_t, mem_t*>> make_mems(const char* arg)
     if (!*p || *p != ':')
       help();
     auto size = strtoull(p + 1, &p, 0);
-    if ((size | base) % PGSIZE != 0)
+
+    // page-align base and size
+    auto base0 = base, size0 = size;
+    size += base0 % PGSIZE;
+    base -= base0 % PGSIZE;
+    if (size % PGSIZE != 0)
+      size += PGSIZE - size % PGSIZE;
+
+    if (base + size < base)
       help();
+
+    if (size != size0) {
+      fprintf(stderr, "Warning: the memory at  [0x%llX, 0x%llX] has been realigned\n"
+                      "to the %ld KiB page size: [0x%llX, 0x%llX]\n",
+              base0, base0 + size0 - 1, PGSIZE / 1024, base, base + size - 1);
+    }
+
     res.push_back(std::make_pair(reg_t(base), new mem_t(size)));
     if (!*p)
       break;
-- 
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