OcDebugLogLib: Implement OcPrintScreen

Include/Library/OcDebugLogLib.h

@@ -36,4 +36,18 @@ OcConfigureLogProtocol (
   IN UINTN               HaltLevel
   );
 
+/**
+  Prints via gST->ConOut without any pool allocations.
+  Otherwise equivalent to Print.
+  Note: EFIAPI must be present for VA_ARGS forwarding (causes bugs with gcc).
+
+  @param[in]  Format  Formatted string.
+**/
+VOID
+EFIAPI
+OcPrintScreen (
+  IN  CONST CHAR16   *Format,
+  ...
+  );
+
 #endif // OC_DEBUG_LOG_LIB_H

Include/Library/OcMiscLib.h

@@ -18,7 +18,11 @@
 #include <Uefi.h>
 #include <Library/OcStringLib.h>
 
-// Base64Decode
+/**
+  Convert seconds to microseconds for use in e.g. gBS->Stall.
+**/
+#define SECONDS_TO_MICROSECONDS(x) ((x)*1000000)
+
 /**
 
   TODO: edk2 now has its implementation in BaseLib, review it and use once it appears in UDK.

Library/OcDebugLogLib/OcDebugLogLib.c

@@ -267,3 +267,34 @@ DebugPrintLevelEnabled (
 {
   return (BOOLEAN) ((ErrorLevel & PcdGet32 (PcdFixedDebugPrintErrorLevel)) != 0);
 }
+
+/**
+  Prints via gST->ConOut without any pool allocations.
+  Otherwise equivalent to Print.
+  Note: EFIAPI must be present for VA_ARGS forwarding (causes bugs with gcc).
+
+  @param[in]  Format  Formatted string.
+**/
+VOID
+EFIAPI
+OcPrintScreen (
+  IN  CONST CHAR16   *Format,
+  ...
+  )
+{
+  CHAR16 Buffer[1024];
+  VA_LIST Marker;
+
+  VA_START (Marker, Format);
+  UnicodeVSPrint (Buffer, sizeof (Buffer), Format, Marker);
+  VA_END (Marker);
+
+  //
+  // It is safe to call gST->ConOut->OutputString, because in crtitical areas
+  // AptioMemoryFix is responsible for overriding gBS->AllocatePool with its own
+  // implementation that uses a custom allocator.
+  //
+  if (gST->ConOut) {
+    gST->ConOut->OutputString (gST->ConOut, Buffer);
+  }
+}