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/** @file
64-bit Math Worker Function.
The 32-bit versions of C compiler generate calls to library routines
to handle 64-bit math. These functions use non-standard calling conventions.
Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
/*
* Shifts a 64-bit unsigned value right by a certain number of bits.
*/
__declspec(naked) void __cdecl _aullshr (void)
{
_asm {
;
; Checking: Only handle 64bit shifting or more
;
cmp cl, 64
jae _Exit
;
; Handle shifting between 0 and 31 bits
;
cmp cl, 32
jae More32
shrd eax, edx, cl
shr edx, cl
ret
;
; Handle shifting of 32-63 bits
;
More32:
mov eax, edx
xor edx, edx
and cl, 31
shr eax, cl
ret
;
; Invalid number (less then 32bits), return 0
;
_Exit:
xor eax, eax
xor edx, edx
ret
}
}
|
