text: #include <linux/bug.h>
  #include <linux/kernel.h>
  #include <asm/opcodes.h>
  
  static unsigned long
  __arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)
  {
  	unsigned long s, j1, j2, i1, i2, imm10, imm11;
  	unsigned long first, second;
  	long offset;
  
  	offset = (long)addr - (long)(pc + 4);
  	if (offset < -16777216 || offset > 16777214) {
  		WARN_ON_ONCE(1);
  		return 0;
  	}
  
  	s	= (offset >> 24) & 0x1;
  	i1	= (offset >> 23) & 0x1;
  	i2	= (offset >> 22) & 0x1;
  	imm10	= (offset >> 12) & 0x3ff;
  	imm11	= (offset >>  1) & 0x7ff;
  
  	j1 = (!i1) ^ s;
  	j2 = (!i2) ^ s;
  
  	first = 0xf000 | (s << 10) | imm10;
  	second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;
  	if (link)
  		second |= 1 << 14;
  
  	return __opcode_thumb32_compose(first, second);
  }
  
  static unsigned long
  __arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)
  {
  	unsigned long opcode = 0xea000000;
  	long offset;
  
  	if (link)
  		opcode |= 1 << 24;
  
  	offset = (long)addr - (long)(pc + 8);
  	if (unlikely(offset < -33554432 || offset > 33554428)) {
  		WARN_ON_ONCE(1);
  		return 0;
  	}
  
  	offset = (offset >> 2) & 0x00ffffff;
  
  	return opcode | offset;
  }
  
  unsigned long
  __arm_gen_branch(unsigned long pc, unsigned long addr, bool link)
  {
  	if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
  		return __arm_gen_branch_thumb2(pc, addr, link);
  	else
  		return __arm_gen_branch_arm(pc, addr, link);
  }
  