diff options
Diffstat (limited to 'qtmips_machine/alu.cpp')
| -rw-r--r-- | qtmips_machine/alu.cpp | 83 |
1 files changed, 79 insertions, 4 deletions
diff --git a/qtmips_machine/alu.cpp b/qtmips_machine/alu.cpp index 79194c9..c86331b 100644 --- a/qtmips_machine/alu.cpp +++ b/qtmips_machine/alu.cpp @@ -39,6 +39,59 @@ using namespace machine; +#if defined(__GNUC__) && __GNUC__ >= 4 + +static inline std::uint32_t alu_op_clz(std::uint32_t n) +{ + int intbits = sizeof(int) * CHAR_BIT; + if (n == 0) + return 32; + return __builtin_clz(n) - (intbits - 32); +} + +#else /* Fallback for generic compiler */ + +// see https://en.wikipedia.org/wiki/Find_first_set#CLZ +static const std::uint8_t sig_table_4bit[16] = + { 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 }; + +static inline std::uint32_t alu_op_clz(std::uint32_t n) +{ + int len = 32; + + if (n & 0xFFFF0000) { + len -= 16; + n >>= 16; + } + if (n & 0xFF00) { + len -= 8; + n >>= 8; + } + if (n & 0xF0) { + len -= 4; + n >>= 4; + } + len -= sig_table_4bit[n]; + return len; +} + +#endif /* end of mips_clz */ + +static inline std::uint64_t alu_read_hi_lo_64bit(Registers *regs) +{ + std::uint64_t val; + val = regs->read_hi_lo(false); + val |= (std::uint64_t)regs->read_hi_lo(true) << 32; + return val; +} + +static inline void alu_write_hi_lo_64bit(Registers *regs, std::uint64_t val) +{ + regs->write_hi_lo(false, (std::uint32_t)(val & 0xffffffff)); + regs->write_hi_lo(true, (std::uint32_t)(val >> 32)); +} + + std::uint32_t machine::alu_operate(enum AluOp operation, std::uint32_t s, std::uint32_t t, std::uint8_t sa, std::uint8_t sz, Registers *regs, bool &discard) { @@ -83,13 +136,11 @@ std::uint32_t machine::alu_operate(enum AluOp operation, std::uint32_t s, std::u return 0x0; case ALU_OP_MULT: s64_val = (std::int64_t)(std::int32_t)s * (std::int32_t)t; - regs->write_hi_lo(false, (std::uint32_t)(s64_val & 0xffffffff)); - regs->write_hi_lo(true, (std::uint32_t)(s64_val >> 32)); + alu_write_hi_lo_64bit(regs, (std::uint64_t)s64_val); return 0x0; case ALU_OP_MULTU: u64_val = (std::uint64_t)s * t; - regs->write_hi_lo(false, (std::uint32_t)(u64_val & 0xffffffff)); - regs->write_hi_lo(true, (std::uint32_t)(u64_val >> 32)); + alu_write_hi_lo_64bit(regs, u64_val); return 0x0; case ALU_OP_DIV: regs->write_hi_lo(false, (std::uint32_t)((std::int32_t)s / (std::int32_t)t)); @@ -130,12 +181,36 @@ std::uint32_t machine::alu_operate(enum AluOp operation, std::uint32_t s, std::u return (s < t) ? 1 : 0; case ALU_OP_MUL: return (std::uint32_t)((std::int32_t)s * (std::int32_t)t); + case ALU_OP_MADD: + s64_val = (std::int64_t)alu_read_hi_lo_64bit(regs); + s64_val += (std::int64_t)(std::int32_t)s * (std::int32_t)t; + alu_write_hi_lo_64bit(regs, (std::uint64_t)s64_val); + return 0x0; + case ALU_OP_MADDU: + u64_val = alu_read_hi_lo_64bit(regs); + u64_val += (std::uint64_t)s * t; + alu_write_hi_lo_64bit(regs, u64_val); + return 0x0; + case ALU_OP_MSUB: + s64_val = (std::int64_t)alu_read_hi_lo_64bit(regs); + s64_val -= (std::int64_t)(std::int32_t)s * (std::int32_t)t; + alu_write_hi_lo_64bit(regs, (std::uint64_t)s64_val); + return 0x0; + case ALU_OP_MSUBU: + u64_val = alu_read_hi_lo_64bit(regs); + u64_val -= (std::uint64_t)s * t; + alu_write_hi_lo_64bit(regs, u64_val); + return 0x0; case ALU_OP_LUI: return t << 16; case ALU_OP_BSHFL: return (uint32_t)(int32_t)(int8_t)t; case ALU_OP_EXT: return (s >> sa) & ((1 << sz) - 1); + case ALU_OP_CLZ: + return alu_op_clz(s); + case ALU_OP_CLO: + return alu_op_clz(~s); case ALU_OP_PASS_T: // Pass s argument without change for JAL return t; case ALU_OP_BREAK: |