stress-branch.c

/*
 * Copyright (C) 2013-2018 Canonical, Ltd.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * This code is a complete clean re-write of the stress tool by
 * Colin Ian King <colin.king@canonical.com> and attempts to be
 * backwardly compatible with the stress tool by Amos Waterland
 * <apw@rossby.metr.ou.edu> but has more stress tests and more
 * functionality.
 *
 */
#include "stress-ng.h"

/*
 *  The following jumps to a random label. If do_more is false
 *  then we jump to label ret and abort. This has been carefully
 *  hand crafted to make each JMP() macro expand to code with
 *  just one jmp statement
 */
#define JMP(a)					\
	label ## a: inc_counter(args);		\
	do_more = g_keep_stressing_flag & 	\
		(!args->max_ops | (*args->counter < args->max_ops)); \
	index = mwc8();				\
	index |= !do_more << 8;			\
	goto *labels[index];

/*
 *  stress_branch()
 *	stress instruction branch prediction
 */
int stress_branch(const args_t *args)
{
	static const void *labels[] = {
		&&label0x00, &&label0x01, &&label0x02, &&label0x03,
		&&label0x04, &&label0x05, &&label0x06, &&label0x07,
		&&label0x08, &&label0x09, &&label0x0a, &&label0x0b,
		&&label0x0c, &&label0x0d, &&label0x0e, &&label0x0f,
		&&label0x10, &&label0x11, &&label0x12, &&label0x13,
		&&label0x14, &&label0x15, &&label0x16, &&label0x17,
		&&label0x18, &&label0x19, &&label0x1a, &&label0x1b,
		&&label0x1c, &&label0x1d, &&label0x1e, &&label0x1f,
		&&label0x20, &&label0x21, &&label0x22, &&label0x23,
		&&label0x24, &&label0x25, &&label0x26, &&label0x27,
		&&label0x28, &&label0x29, &&label0x2a, &&label0x2b,
		&&label0x2c, &&label0x2d, &&label0x2e, &&label0x2f,
		&&label0x30, &&label0x31, &&label0x32, &&label0x33,
		&&label0x34, &&label0x35, &&label0x36, &&label0x37,
		&&label0x38, &&label0x39, &&label0x3a, &&label0x3b,
		&&label0x3c, &&label0x3d, &&label0x3e, &&label0x3f,

		&&label0x40, &&label0x41, &&label0x42, &&label0x43,
		&&label0x44, &&label0x45, &&label0x46, &&label0x47,
		&&label0x48, &&label0x49, &&label0x4a, &&label0x4b,
		&&label0x4c, &&label0x4d, &&label0x4e, &&label0x4f,
		&&label0x50, &&label0x51, &&label0x52, &&label0x53,
		&&label0x54, &&label0x55, &&label0x56, &&label0x57,
		&&label0x58, &&label0x59, &&label0x5a, &&label0x5b,
		&&label0x5c, &&label0x5d, &&label0x5e, &&label0x5f,
		&&label0x60, &&label0x61, &&label0x62, &&label0x63,
		&&label0x64, &&label0x65, &&label0x66, &&label0x67,
		&&label0x68, &&label0x69, &&label0x6a, &&label0x6b,
		&&label0x6c, &&label0x6d, &&label0x6e, &&label0x6f,
		&&label0x70, &&label0x71, &&label0x72, &&label0x73,
		&&label0x74, &&label0x75, &&label0x76, &&label0x77,
		&&label0x78, &&label0x79, &&label0x7a, &&label0x7b,
		&&label0x7c, &&label0x7d, &&label0x7e, &&label0x7f,

		&&label0x80, &&label0x81, &&label0x82, &&label0x83,
		&&label0x84, &&label0x85, &&label0x86, &&label0x87,
		&&label0x88, &&label0x89, &&label0x8a, &&label0x8b,
		&&label0x8c, &&label0x8d, &&label0x8e, &&label0x8f,
		&&label0x90, &&label0x91, &&label0x92, &&label0x93,
		&&label0x94, &&label0x95, &&label0x96, &&label0x97,
		&&label0x98, &&label0x99, &&label0x9a, &&label0x9b,
		&&label0x9c, &&label0x9d, &&label0x9e, &&label0x9f,
		&&label0xa0, &&label0xa1, &&label0xa2, &&label0xa3,
		&&label0xa4, &&label0xa5, &&label0xa6, &&label0xa7,
		&&label0xa8, &&label0xa9, &&label0xaa, &&label0xab,
		&&label0xac, &&label0xad, &&label0xae, &&label0xaf,
		&&label0xb0, &&label0xb1, &&label0xb2, &&label0xb3,
		&&label0xb4, &&label0xb5, &&label0xb6, &&label0xb7,
		&&label0xb8, &&label0xb9, &&label0xba, &&label0xbb,
		&&label0xbc, &&label0xbd, &&label0xbe, &&label0xbf,

		&&label0xc0, &&label0xc1, &&label0xc2, &&label0xc3,
		&&label0xc4, &&label0xc5, &&label0xc6, &&label0xc7,
		&&label0xc8, &&label0xc9, &&label0xca, &&label0xcb,
		&&label0xcc, &&label0xcd, &&label0xce, &&label0xcf,
		&&label0xd0, &&label0xd1, &&label0xd2, &&label0xd3,
		&&label0xd4, &&label0xd5, &&label0xd6, &&label0xd7,
		&&label0xd8, &&label0xd9, &&label0xda, &&label0xdb,
		&&label0xdc, &&label0xdd, &&label0xde, &&label0xdf,
		&&label0xe0, &&label0xe1, &&label0xe2, &&label0xe3,
		&&label0xe4, &&label0xe5, &&label0xe6, &&label0xe7,
		&&label0xe8, &&label0xe9, &&label0xea, &&label0xeb,
		&&label0xec, &&label0xed, &&label0xee, &&label0xef,
		&&label0xf0, &&label0xf1, &&label0xf2, &&label0xf3,
		&&label0xf4, &&label0xf5, &&label0xf6, &&label0xf7,
		&&label0xf8, &&label0xf9, &&label0xfa, &&label0xfb,
		&&label0xfc, &&label0xfd, &&label0xfe, &&label0xff,

		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,

		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,

		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,

		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
		&&ret, &&ret, &&ret, &&ret,
	};

	for (;;) {
		register bool do_more;
		register uint16_t index;

		JMP(0x00)
		JMP(0x01)
		JMP(0x02)
		JMP(0x03)
		JMP(0x04)
		JMP(0x05)
		JMP(0x06)
		JMP(0x07)
		JMP(0x08)
		JMP(0x09)
		JMP(0x0a)
		JMP(0x0b)
		JMP(0x0c)
		JMP(0x0d)
		JMP(0x0e)
		JMP(0x0f)
		JMP(0x10)
		JMP(0x11)
		JMP(0x12)
		JMP(0x13)
		JMP(0x14)
		JMP(0x15)
		JMP(0x16)
		JMP(0x17)
		JMP(0x18)
		JMP(0x19)
		JMP(0x1a)
		JMP(0x1b)
		JMP(0x1c)
		JMP(0x1d)
		JMP(0x1e)
		JMP(0x1f)
		JMP(0x20)
		JMP(0x21)
		JMP(0x22)
		JMP(0x23)
		JMP(0x24)
		JMP(0x25)
		JMP(0x26)
		JMP(0x27)
		JMP(0x28)
		JMP(0x29)
		JMP(0x2a)
		JMP(0x2b)
		JMP(0x2c)
		JMP(0x2d)
		JMP(0x2e)
		JMP(0x2f)
		JMP(0x30)
		JMP(0x31)
		JMP(0x32)
		JMP(0x33)
		JMP(0x34)
		JMP(0x35)
		JMP(0x36)
		JMP(0x37)
		JMP(0x38)
		JMP(0x39)
		JMP(0x3a)
		JMP(0x3b)
		JMP(0x3c)
		JMP(0x3d)
		JMP(0x3e)
		JMP(0x3f)

		JMP(0x40)
		JMP(0x41)
		JMP(0x42)
		JMP(0x43)
		JMP(0x44)
		JMP(0x45)
		JMP(0x46)
		JMP(0x47)
		JMP(0x48)
		JMP(0x49)
		JMP(0x4a)
		JMP(0x4b)
		JMP(0x4c)
		JMP(0x4d)
		JMP(0x4e)
		JMP(0x4f)
		JMP(0x50)
		JMP(0x51)
		JMP(0x52)
		JMP(0x53)
		JMP(0x54)
		JMP(0x55)
		JMP(0x56)
		JMP(0x57)
		JMP(0x58)
		JMP(0x59)
		JMP(0x5a)
		JMP(0x5b)
		JMP(0x5c)
		JMP(0x5d)
		JMP(0x5e)
		JMP(0x5f)
		JMP(0x60)
		JMP(0x61)
		JMP(0x62)
		JMP(0x63)
		JMP(0x64)
		JMP(0x65)
		JMP(0x66)
		JMP(0x67)
		JMP(0x68)
		JMP(0x69)
		JMP(0x6a)
		JMP(0x6b)
		JMP(0x6c)
		JMP(0x6d)
		JMP(0x6e)
		JMP(0x6f)
		JMP(0x70)
		JMP(0x71)
		JMP(0x72)
		JMP(0x73)
		JMP(0x74)
		JMP(0x75)
		JMP(0x76)
		JMP(0x77)
		JMP(0x78)
		JMP(0x79)
		JMP(0x7a)
		JMP(0x7b)
		JMP(0x7c)
		JMP(0x7d)
		JMP(0x7e)
		JMP(0x7f)

		JMP(0x80)
		JMP(0x81)
		JMP(0x82)
		JMP(0x83)
		JMP(0x84)
		JMP(0x85)
		JMP(0x86)
		JMP(0x87)
		JMP(0x88)
		JMP(0x89)
		JMP(0x8a)
		JMP(0x8b)
		JMP(0x8c)
		JMP(0x8d)
		JMP(0x8e)
		JMP(0x8f)
		JMP(0x90)
		JMP(0x91)
		JMP(0x92)
		JMP(0x93)
		JMP(0x94)
		JMP(0x95)
		JMP(0x96)
		JMP(0x97)
		JMP(0x98)
		JMP(0x99)
		JMP(0x9a)
		JMP(0x9b)
		JMP(0x9c)
		JMP(0x9d)
		JMP(0x9e)
		JMP(0x9f)
		JMP(0xa0)
		JMP(0xa1)
		JMP(0xa2)
		JMP(0xa3)
		JMP(0xa4)
		JMP(0xa5)
		JMP(0xa6)
		JMP(0xa7)
		JMP(0xa8)
		JMP(0xa9)
		JMP(0xaa)
		JMP(0xab)
		JMP(0xac)
		JMP(0xad)
		JMP(0xae)
		JMP(0xaf)
		JMP(0xb0)
		JMP(0xb1)
		JMP(0xb2)
		JMP(0xb3)
		JMP(0xb4)
		JMP(0xb5)
		JMP(0xb6)
		JMP(0xb7)
		JMP(0xb8)
		JMP(0xb9)
		JMP(0xba)
		JMP(0xbb)
		JMP(0xbc)
		JMP(0xbd)
		JMP(0xbe)
		JMP(0xbf)

		JMP(0xc0)
		JMP(0xc1)
		JMP(0xc2)
		JMP(0xc3)
		JMP(0xc4)
		JMP(0xc5)
		JMP(0xc6)
		JMP(0xc7)
		JMP(0xc8)
		JMP(0xc9)
		JMP(0xca)
		JMP(0xcb)
		JMP(0xcc)
		JMP(0xcd)
		JMP(0xce)
		JMP(0xcf)
		JMP(0xd0)
		JMP(0xd1)
		JMP(0xd2)
		JMP(0xd3)
		JMP(0xd4)
		JMP(0xd5)
		JMP(0xd6)
		JMP(0xd7)
		JMP(0xd8)
		JMP(0xd9)
		JMP(0xda)
		JMP(0xdb)
		JMP(0xdc)
		JMP(0xdd)
		JMP(0xde)
		JMP(0xdf)
		JMP(0xe0)
		JMP(0xe1)
		JMP(0xe2)
		JMP(0xe3)
		JMP(0xe4)
		JMP(0xe5)
		JMP(0xe6)
		JMP(0xe7)
		JMP(0xe8)
		JMP(0xe9)
		JMP(0xea)
		JMP(0xeb)
		JMP(0xec)
		JMP(0xed)
		JMP(0xee)
		JMP(0xef)
		JMP(0xf0)
		JMP(0xf1)
		JMP(0xf2)
		JMP(0xf3)
		JMP(0xf4)
		JMP(0xf5)
		JMP(0xf6)
		JMP(0xf7)
		JMP(0xf8)
		JMP(0xf9)
		JMP(0xfa)
		JMP(0xfb)
		JMP(0xfc)
		JMP(0xfd)
		JMP(0xfe)
		JMP(0xff)
	}
ret:
	return EXIT_SUCCESS;
}