1. 根目录:
2. arch
3. mips
4. include
5. asm
6. branch.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1996, 1997, 1998, 2001 by Ralf Baechle
 */
#ifndef _ASM_BRANCH_H
#define _ASM_BRANCH_H

#include <asm/cpu-features.h>
#include <asm/mipsregs.h>
#include <asm/ptrace.h>
#include <asm/inst.h>

extern int __isa_exception_epc(struct pt_regs *regs);
extern int __compute_return_epc(struct pt_regs *regs);
extern int __compute_return_epc_for_insn(struct pt_regs *regs,
					 union mips_instruction insn);
extern int __microMIPS_compute_return_epc(struct pt_regs *regs);
extern int __MIPS16e_compute_return_epc(struct pt_regs *regs);

/*
 * microMIPS bitfields
 */
#define MM_POOL32A_MINOR_MASK	0x3f
#define MM_POOL32A_MINOR_SHIFT	0x6
#define MM_MIPS32_COND_FC	0x30

extern int __mm_isBranchInstr(struct pt_regs *regs,
	struct mm_decoded_insn dec_insn, unsigned long *contpc);

static inline int mm_isBranchInstr(struct pt_regs *regs,
	struct mm_decoded_insn dec_insn, unsigned long *contpc)
{
	if (!cpu_has_mmips)
		return 0;

	return __mm_isBranchInstr(regs, dec_insn, contpc);
}

static inline int delay_slot(struct pt_regs *regs)
{
	return regs->cp0_cause & CAUSEF_BD;
}

static inline void clear_delay_slot(struct pt_regs *regs)
{
	regs->cp0_cause &= ~CAUSEF_BD;
}

static inline void set_delay_slot(struct pt_regs *regs)
{
	regs->cp0_cause |= CAUSEF_BD;
}

static inline unsigned long exception_epc(struct pt_regs *regs)
{
	if (likely(!delay_slot(regs)))
		return regs->cp0_epc;

	if (get_isa16_mode(regs->cp0_epc))
		return __isa_exception_epc(regs);

	return regs->cp0_epc + 4;
}

#define BRANCH_LIKELY_TAKEN 0x0001

static inline int compute_return_epc(struct pt_regs *regs)
{
	if (get_isa16_mode(regs->cp0_epc)) {
		if (cpu_has_mmips)
			return __microMIPS_compute_return_epc(regs);
		if (cpu_has_mips16)
			return __MIPS16e_compute_return_epc(regs);
		return regs->cp0_epc;
	}

	if (!delay_slot(regs)) {
		regs->cp0_epc += 4;
		return 0;
	}

	return __compute_return_epc(regs);
}

static inline int MIPS16e_compute_return_epc(struct pt_regs *regs,
					     union mips16e_instruction *inst)
{
	if (likely(!delay_slot(regs))) {
		if (inst->ri.opcode == MIPS16e_extend_op) {
			regs->cp0_epc += 4;
			return 0;
		}
		regs->cp0_epc += 2;
		return 0;
	}

	return __MIPS16e_compute_return_epc(regs);
}

#endif /* _ASM_BRANCH_H */