diff options
Diffstat (limited to 'sim/aarch64/simulator.c')
| -rw-r--r-- | sim/aarch64/simulator.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/sim/aarch64/simulator.c b/sim/aarch64/simulator.c index 1756ba11825..8a8df7a2732 100644 --- a/sim/aarch64/simulator.c +++ b/sim/aarch64/simulator.c @@ -13020,6 +13020,8 @@ mul64hi (uint64_t value1, uint64_t value2) /* Drop lowest 32 bits of middle cross-product. */ result = resultmid1 >> 32; + /* Move carry bit to just above middle cross-product highest bit. */ + carry = carry << 32; /* Add top cross-product plus and any carry. */ result += xproducthi + carry; @@ -13042,7 +13044,7 @@ smulh (sim_cpu *cpu) int64_t value2 = aarch64_get_reg_u64 (cpu, rm, NO_SP); uint64_t uvalue1; uint64_t uvalue2; - int64_t signum = 1; + int negate = 0; if (ra != R31) HALT_UNALLOC; @@ -13051,7 +13053,7 @@ smulh (sim_cpu *cpu) the fix the sign up afterwards. */ if (value1 < 0) { - signum *= -1L; + negate = !negate; uvalue1 = -value1; } else @@ -13061,7 +13063,7 @@ smulh (sim_cpu *cpu) if (value2 < 0) { - signum *= -1L; + negate = !negate; uvalue2 = -value2; } else @@ -13070,9 +13072,18 @@ smulh (sim_cpu *cpu) } TRACE_DECODE (cpu, "emulated at line %d", __LINE__); + uresult = mul64hi (uvalue1, uvalue2); result = uresult; - result *= signum; + + if (negate) + { + /* Multiply 128-bit result by -1, which means highpart gets inverted, + and has carry in added only if low part is 0. */ + result = ~result; + if ((uvalue1 * uvalue2) == 0) + result += 1; + } aarch64_set_reg_s64 (cpu, rd, NO_SP, result); } |