1. Added comments to ASM files

[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / WriteMsr64.asm

diff --git a/MdePkg/Library/BaseLib/X64/WriteMsr64.asm b/MdePkg/Library/BaseLib/X64/WriteMsr64.asm
index 6b8066f922ccef426aa2d188216122bf92582be5..b7704b81853048f47c9340f71d0a3be058719618 100644 (file)
--- a/MdePkg/Library/BaseLib/X64/WriteMsr64.asm
+++ b/MdePkg/Library/BaseLib/X64/WriteMsr64.asm
@@ -32,8 +32,8 @@
 ;   );\r
 ;------------------------------------------------------------------------------\r
 AsmWriteMsr64   PROC\r
-    mov     rax, rdx\r
-    shr     rdx, 20h\r
+    mov     rax, rdx                    ; meanwhile, rax <- return value\r
+    shr     rdx, 20h                    ; edx:eax contains the value to write\r
     wrmsr\r
     ret\r
 AsmWriteMsr64   ENDP\r