diff options
Diffstat (limited to 'target/ppc/int_helper.c')
| -rw-r--r-- | target/ppc/int_helper.c | 61 |
1 files changed, 48 insertions, 13 deletions
diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c index c2d3248d1e..f5dac3aa87 100644 --- a/target/ppc/int_helper.c +++ b/target/ppc/int_helper.c @@ -2480,10 +2480,26 @@ uint32_t helper_bcdctz(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps) return cr; } +/** + * Compare 2 128-bit unsigned integers, passed in as unsigned 64-bit pairs + * + * Returns: + * > 0 if ahi|alo > bhi|blo, + * 0 if ahi|alo == bhi|blo, + * < 0 if ahi|alo < bhi|blo + */ +static inline int ucmp128(uint64_t alo, uint64_t ahi, + uint64_t blo, uint64_t bhi) +{ + return (ahi == bhi) ? + (alo > blo ? 1 : (alo == blo ? 0 : -1)) : + (ahi > bhi ? 1 : -1); +} + uint32_t helper_bcdcfsq(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps) { int i; - int cr = 0; + int cr; uint64_t lo_value; uint64_t hi_value; ppc_avr_t ret = { .u64 = { 0, 0 } }; @@ -2492,28 +2508,47 @@ uint32_t helper_bcdcfsq(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps) lo_value = -b->VsrSD(1); hi_value = ~b->VsrD(0) + !lo_value; bcd_put_digit(&ret, 0xD, 0); + + cr = CRF_LT; } else { lo_value = b->VsrD(1); hi_value = b->VsrD(0); bcd_put_digit(&ret, bcd_preferred_sgn(0, ps), 0); - } - if (divu128(&lo_value, &hi_value, 1000000000000000ULL) || - lo_value > 9999999999999999ULL) { - cr = CRF_SO; + if (hi_value == 0 && lo_value == 0) { + cr = CRF_EQ; + } else { + cr = CRF_GT; + } } - for (i = 1; i < 16; hi_value /= 10, i++) { - bcd_put_digit(&ret, hi_value % 10, i); - } + /* + * Check src limits: abs(src) <= 10^31 - 1 + * + * 10^31 - 1 = 0x0000007e37be2022 c0914b267fffffff + */ + if (ucmp128(lo_value, hi_value, + 0xc0914b267fffffffULL, 0x7e37be2022ULL) > 0) { + cr |= CRF_SO; - for (; i < 32; lo_value /= 10, i++) { - bcd_put_digit(&ret, lo_value % 10, i); - } + /* + * According to the ISA, if src wouldn't fit in the destination + * register, the result is undefined. + * In that case, we leave r unchanged. + */ + } else { + divu128(&lo_value, &hi_value, 1000000000000000ULL); - cr |= bcd_cmp_zero(&ret); + for (i = 1; i < 16; hi_value /= 10, i++) { + bcd_put_digit(&ret, hi_value % 10, i); + } - *r = ret; + for (; i < 32; lo_value /= 10, i++) { + bcd_put_digit(&ret, lo_value % 10, i); + } + + *r = ret; + } return cr; } |