From: Ben Pfaff <blp@cs.stanford.edu>
Date: Thu, 26 Aug 2004 19:01:02 +0000 (+0000)
Subject: Optimize filesys_stub_get_bytes().
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30e5bb633c98deda3cc2c5743819714577eb08be;p=pintos-anon

Optimize filesys_stub_get_bytes().
---

diff --git a/src/filesys/filesys-stub.c b/src/filesys/filesys-stub.c
index 29c4cb9..edf5de2 100644
--- a/src/filesys/filesys-stub.c
+++ b/src/filesys/filesys-stub.c
@@ -84,7 +84,11 @@ filesys_stub_get_bool (void)
 void 
 filesys_stub_get_bytes (void *buffer, size_t size)
 {
-  backdoor_get_bytes (buffer, size, in_byte, NULL);
+  /* We could use backdoor_get_bytes() but this is significantly
+     faster. */
+  asm ("rep insl; movl %0, %%ecx; rep insb"
+       :
+       : "g" (size % 4), "d" (0x8901), "c" (size / 4), "D" (buffer));
 }
 
 struct file *