// See Assembler::nop(type).
ASSERT(type < 32);
uint32_t opcode = GetOpcodeField(instr);
+ uint32_t function = GetFunctionField(instr);
uint32_t rt = GetRt(instr);
- uint32_t rs = GetRs(instr);
+ uint32_t rd = GetRd(instr);
uint32_t sa = GetSa(instr);
- // nop(type) == sll(zero_reg, zero_reg, type);
- // Technically all these values will be 0 but
- // this makes more sense to the reader.
+ // Traditional mips nop == sll(zero_reg, zero_reg, 0)
+ // When marking non-zero type, use sll(zero_reg, at, type)
+ // to avoid use of mips ssnop and ehb special encodings
+ // of the sll instruction.
- bool ret = (opcode == SLL &&
- rt == static_cast<uint32_t>(ToNumber(zero_reg)) &&
- rs == static_cast<uint32_t>(ToNumber(zero_reg)) &&
+ Register nop_rt_reg = (type == 0) ? zero_reg : at;
+ bool ret = (opcode == SPECIAL && function == SLL &&
+ rd == static_cast<uint32_t>(ToNumber(zero_reg)) &&
+ rt == static_cast<uint32_t>(ToNumber(nop_rt_reg)) &&
sa == type);
return ret;
FIRST_IC_MARKER = PROPERTY_ACCESS_INLINED
};
- // Type == 0 is the default non-marking type.
+ // Type == 0 is the default non-marking nop. For mips this is a
+ // sll(zero_reg, zero_reg, 0). We use rt_reg == at for non-zero
+ // marking, to avoid conflict with ssnop and ehb instructions.
void nop(unsigned int type = 0) {
ASSERT(type < 32);
- sll(zero_reg, zero_reg, type, true);
+ Register nop_rt_reg = (type == 0) ? zero_reg : at;
+ sll(zero_reg, nop_rt_reg, type, true);
}