xref: /aosp_15_r20/external/compiler-rt/lib/builtins/i386/ashrdi3.S (revision 7c3d14c8b49c529e04be81a3ce6f5cc23712e4c6)
1*7c3d14c8STreehugger Robot// This file is dual licensed under the MIT and the University of Illinois Open
2*7c3d14c8STreehugger Robot// Source Licenses. See LICENSE.TXT for details.
3*7c3d14c8STreehugger Robot
4*7c3d14c8STreehugger Robot#include "../assembly.h"
5*7c3d14c8STreehugger Robot
6*7c3d14c8STreehugger Robot// di_int __ashrdi3(di_int input, int count);
7*7c3d14c8STreehugger Robot
8*7c3d14c8STreehugger Robot#ifdef __i386__
9*7c3d14c8STreehugger Robot#ifdef __SSE2__
10*7c3d14c8STreehugger Robot
11*7c3d14c8STreehugger Robot.text
12*7c3d14c8STreehugger Robot.balign 4
13*7c3d14c8STreehugger RobotDEFINE_COMPILERRT_FUNCTION(__ashrdi3)
14*7c3d14c8STreehugger Robot	movd	  12(%esp),		%xmm2	// Load count
15*7c3d14c8STreehugger Robot	movl	   8(%esp),		%eax
16*7c3d14c8STreehugger Robot#ifndef TRUST_CALLERS_USE_64_BIT_STORES
17*7c3d14c8STreehugger Robot	movd	   4(%esp),		%xmm0
18*7c3d14c8STreehugger Robot	movd	   8(%esp),		%xmm1
19*7c3d14c8STreehugger Robot	punpckldq	%xmm1,		%xmm0	// Load input
20*7c3d14c8STreehugger Robot#else
21*7c3d14c8STreehugger Robot	movq	   4(%esp),		%xmm0	// Load input
22*7c3d14c8STreehugger Robot#endif
23*7c3d14c8STreehugger Robot
24*7c3d14c8STreehugger Robot	psrlq		%xmm2,		%xmm0	// unsigned shift input by count
25*7c3d14c8STreehugger Robot
26*7c3d14c8STreehugger Robot	testl		%eax,		%eax	// check the sign-bit of the input
27*7c3d14c8STreehugger Robot	jns			1f					// early out for positive inputs
28*7c3d14c8STreehugger Robot
29*7c3d14c8STreehugger Robot	// If the input is negative, we need to construct the shifted sign bit
30*7c3d14c8STreehugger Robot	// to or into the result, as xmm does not have a signed right shift.
31*7c3d14c8STreehugger Robot	pcmpeqb		%xmm1,		%xmm1	// -1ULL
32*7c3d14c8STreehugger Robot	psrlq		$58,		%xmm1	// 0x3f
33*7c3d14c8STreehugger Robot	pandn		%xmm1,		%xmm2	// 63 - count
34*7c3d14c8STreehugger Robot	pcmpeqb		%xmm1,		%xmm1	// -1ULL
35*7c3d14c8STreehugger Robot	psubq		%xmm1,		%xmm2	// 64 - count
36*7c3d14c8STreehugger Robot	psllq		%xmm2,		%xmm1	// -1 << (64 - count) = leading sign bits
37*7c3d14c8STreehugger Robot	por			%xmm1,		%xmm0
38*7c3d14c8STreehugger Robot
39*7c3d14c8STreehugger Robot	// Move the result back to the general purpose registers and return
40*7c3d14c8STreehugger Robot1:	movd		%xmm0,		%eax
41*7c3d14c8STreehugger Robot	psrlq		$32,		%xmm0
42*7c3d14c8STreehugger Robot	movd		%xmm0,		%edx
43*7c3d14c8STreehugger Robot	ret
44*7c3d14c8STreehugger RobotEND_COMPILERRT_FUNCTION(__ashrdi3)
45*7c3d14c8STreehugger Robot
46*7c3d14c8STreehugger Robot#else // Use GPRs instead of SSE2 instructions, if they aren't available.
47*7c3d14c8STreehugger Robot
48*7c3d14c8STreehugger Robot.text
49*7c3d14c8STreehugger Robot.balign 4
50*7c3d14c8STreehugger RobotDEFINE_COMPILERRT_FUNCTION(__ashrdi3)
51*7c3d14c8STreehugger Robot	movl	  12(%esp),		%ecx	// Load count
52*7c3d14c8STreehugger Robot	movl	   8(%esp),		%edx	// Load high
53*7c3d14c8STreehugger Robot	movl	   4(%esp),		%eax	// Load low
54*7c3d14c8STreehugger Robot
55*7c3d14c8STreehugger Robot	testl		$0x20,		%ecx	// If count >= 32
56*7c3d14c8STreehugger Robot	jnz			1f					//    goto 1
57*7c3d14c8STreehugger Robot
58*7c3d14c8STreehugger Robot	shrdl		%cl, %edx,	%eax	// right shift low by count
59*7c3d14c8STreehugger Robot	sarl		%cl,		%edx	// right shift high by count
60*7c3d14c8STreehugger Robot	ret
61*7c3d14c8STreehugger Robot
62*7c3d14c8STreehugger Robot1:	movl		%edx,		%eax	// Move high to low
63*7c3d14c8STreehugger Robot	sarl		$31,		%edx	// clear high
64*7c3d14c8STreehugger Robot	sarl		%cl,		%eax	// shift low by count - 32
65*7c3d14c8STreehugger Robot	ret
66*7c3d14c8STreehugger RobotEND_COMPILERRT_FUNCTION(__ashrdi3)
67*7c3d14c8STreehugger Robot
68*7c3d14c8STreehugger Robot#endif // __SSE2__
69*7c3d14c8STreehugger Robot#endif // __i386__
70*7c3d14c8STreehugger Robot
71*7c3d14c8STreehugger RobotNO_EXEC_STACK_DIRECTIVE
72*7c3d14c8STreehugger Robot
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