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OvmfPkg: QemuVideoDxe: the VBE shim needs no 64-bit shifts (VS2010)

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The SegmentC local variable has type EFI_PHYSICAL_ADDRESS for (justified)
style reasons. However, the 64-bit bit-shifts that it undergoes result in
intrinsic calls when built with VS2010 for Ia32 / NOOPT.

The concrete value of SegmentC, 0xC0000, and the results  of the bitops
that are based on it, are statically computeable. Cast SegmentC to UINT32
before subjecting it to bitwise operations; we can see in advance that
this won't lead to range loss.

Contributed-under: TianoCore Contribution Agreement 1.0

Signed-off-by: Scott Duplichan <scott@notabs.org>

[lersek@redhat.com: dropped now superfluous outermost parens; commit msg]

Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Build-tested-by: Scott Duplichan <scott@notabs.org>

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16385 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Scott Duplichan 2014-11-14 10:23:55 +00:00 committed by lersek
parent f7e899c7c7
commit 75f8e3aaff
1 changed files with 6 additions and 6 deletions
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12
OvmfPkg/QemuVideoDxe/VbeShim.c
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@ -153,13 +153,13 @@ InstallVbeShim (
CopyMem (VbeInfo->Signature, "VESA", 4); CopyMem (VbeInfo->Signature, "VESA", 4);
VbeInfo->VesaVersion = 0x0300; VbeInfo->VesaVersion = 0x0300;
VbeInfo->OemNameAddress = (UINT32)(SegmentC << 12 | (UINT16)(UINTN)Ptr); VbeInfo->OemNameAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
CopyMem (Ptr, "QEMU", 5); CopyMem (Ptr, "QEMU", 5);
Ptr += 5; Ptr += 5;
VbeInfo->Capabilities = BIT0; // DAC can be switched into 8-bit mode VbeInfo->Capabilities = BIT0; // DAC can be switched into 8-bit mode
VbeInfo->ModeListAddress = (UINT32)(SegmentC << 12 | (UINT16)(UINTN)Ptr); VbeInfo->ModeListAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
*(UINT16*)Ptr = 0x00f1; // mode number *(UINT16*)Ptr = 0x00f1; // mode number
Ptr += 2; Ptr += 2;
*(UINT16*)Ptr = 0xFFFF; // mode list terminator *(UINT16*)Ptr = 0xFFFF; // mode list terminator
@ -168,17 +168,17 @@ InstallVbeShim (
VbeInfo->VideoMem64K = (UINT16)((1024 * 768 * 4 + 65535) / 65536); VbeInfo->VideoMem64K = (UINT16)((1024 * 768 * 4 + 65535) / 65536);
VbeInfo->OemSoftwareVersion = 0x0000; VbeInfo->OemSoftwareVersion = 0x0000;
VbeInfo->VendorNameAddress = (UINT32)(SegmentC << 12 | (UINT16)(UINTN)Ptr); VbeInfo->VendorNameAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
CopyMem (Ptr, "OVMF", 5); CopyMem (Ptr, "OVMF", 5);
Ptr += 5; Ptr += 5;
VbeInfo->ProductNameAddress = (UINT32)(SegmentC << 12 | (UINT16)(UINTN)Ptr); VbeInfo->ProductNameAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
Printed = AsciiSPrint ((CHAR8 *)Ptr, Printed = AsciiSPrint ((CHAR8 *)Ptr,
sizeof VbeInfoFull->Buffer - (Ptr - VbeInfoFull->Buffer), "%s", sizeof VbeInfoFull->Buffer - (Ptr - VbeInfoFull->Buffer), "%s",
CardName); CardName);
Ptr += Printed + 1; Ptr += Printed + 1;
VbeInfo->ProductRevAddress = (UINT32)(SegmentC << 12 | (UINT16)(UINTN)Ptr); VbeInfo->ProductRevAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
CopyMem (Ptr, mProductRevision, sizeof mProductRevision); CopyMem (Ptr, mProductRevision, sizeof mProductRevision);
Ptr += sizeof mProductRevision; Ptr += sizeof mProductRevision;
@ -268,7 +268,7 @@ InstallVbeShim (
// //
// Second, point the Int10h vector at the shim. // Second, point the Int10h vector at the shim.
// //
Int0x10->Segment = (UINT16) (SegmentC >> 4); Int0x10->Segment = (UINT16) ((UINT32)SegmentC >> 4);
Int0x10->Offset = (UINT16) ((UINTN) (VbeModeInfo + 1) - SegmentC); Int0x10->Offset = (UINT16) ((UINTN) (VbeModeInfo + 1) - SegmentC);
DEBUG ((EFI_D_INFO, "%a: VBE shim installed\n", __FUNCTION__)); DEBUG ((EFI_D_INFO, "%a: VBE shim installed\n", __FUNCTION__));