1. Added comments to ASM files

[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / WriteDr4.asm

diff --git a/MdePkg/Library/BaseLib/X64/WriteDr4.asm b/MdePkg/Library/BaseLib/X64/WriteDr4.asm
index 12b643825b6e462c868a0ea1d70ea3a2e229a676..188a9d4ddcd5d80e13bcc57c6750762f287dd4d3 100644 (file)
--- a/MdePkg/Library/BaseLib/X64/WriteDr4.asm
+++ b/MdePkg/Library/BaseLib/X64/WriteDr4.asm
@@ -27,11 +27,16 @@
 ; UINTN\r
 ; EFIAPI\r
 ; AsmWriteDr4 (\r
-;   VOID\r
+;   IN UINTN Value\r
 ;   );\r
 ;------------------------------------------------------------------------------\r
 AsmWriteDr4 PROC\r
+    ;\r
+    ; There's no obvious reason to access this register, since it's aliased to\r
+    ; DR6 when DE=0 or an exception generated when DE=1\r
+    ;\r
     DB      0fh, 23h, 0e1h\r
+    mov     rax, rcx\r
     ret\r
 AsmWriteDr4 ENDP\r
 \r