diff options
Diffstat (limited to 'target-ppc/int_helper.c')
| -rw-r--r-- | target-ppc/int_helper.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c index 4e8e507819..ce7c6a0ea0 100644 --- a/target-ppc/int_helper.c +++ b/target-ppc/int_helper.c @@ -2136,6 +2136,207 @@ void helper_vsubecuq(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c) #endif } +#define BCD_PLUS_PREF_1 0xC +#define BCD_PLUS_PREF_2 0xF +#define BCD_PLUS_ALT_1 0xA +#define BCD_NEG_PREF 0xD +#define BCD_NEG_ALT 0xB +#define BCD_PLUS_ALT_2 0xE + +#if defined(HOST_WORDS_BIGENDIAN) +#define BCD_DIG_BYTE(n) (15 - (n/2)) +#else +#define BCD_DIG_BYTE(n) (n/2) +#endif + +static int bcd_get_sgn(ppc_avr_t *bcd) +{ + switch (bcd->u8[BCD_DIG_BYTE(0)] & 0xF) { + case BCD_PLUS_PREF_1: + case BCD_PLUS_PREF_2: + case BCD_PLUS_ALT_1: + case BCD_PLUS_ALT_2: + { + return 1; + } + + case BCD_NEG_PREF: + case BCD_NEG_ALT: + { + return -1; + } + + default: + { + return 0; + } + } +} + +static int bcd_preferred_sgn(int sgn, int ps) +{ + if (sgn >= 0) { + return (ps == 0) ? BCD_PLUS_PREF_1 : BCD_PLUS_PREF_2; + } else { + return BCD_NEG_PREF; + } +} + +static uint8_t bcd_get_digit(ppc_avr_t *bcd, int n, int *invalid) +{ + uint8_t result; + if (n & 1) { + result = bcd->u8[BCD_DIG_BYTE(n)] >> 4; + } else { + result = bcd->u8[BCD_DIG_BYTE(n)] & 0xF; + } + + if (unlikely(result > 9)) { + *invalid = true; + } + return result; +} + +static void bcd_put_digit(ppc_avr_t *bcd, uint8_t digit, int n) +{ + if (n & 1) { + bcd->u8[BCD_DIG_BYTE(n)] &= 0x0F; + bcd->u8[BCD_DIG_BYTE(n)] |= (digit<<4); + } else { + bcd->u8[BCD_DIG_BYTE(n)] &= 0xF0; + bcd->u8[BCD_DIG_BYTE(n)] |= digit; + } +} + +static int bcd_cmp_mag(ppc_avr_t *a, ppc_avr_t *b) +{ + int i; + int invalid = 0; + for (i = 31; i > 0; i--) { + uint8_t dig_a = bcd_get_digit(a, i, &invalid); + uint8_t dig_b = bcd_get_digit(b, i, &invalid); + if (unlikely(invalid)) { + return 0; /* doesnt matter */ + } else if (dig_a > dig_b) { + return 1; + } else if (dig_a < dig_b) { + return -1; + } + } + + return 0; +} + +static int bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, + int *overflow) +{ + int carry = 0; + int i; + int is_zero = 1; + for (i = 1; i <= 31; i++) { + uint8_t digit = bcd_get_digit(a, i, invalid) + + bcd_get_digit(b, i, invalid) + carry; + is_zero &= (digit == 0); + if (digit > 9) { + carry = 1; + digit -= 10; + } else { + carry = 0; + } + + bcd_put_digit(t, digit, i); + + if (unlikely(*invalid)) { + return -1; + } + } + + *overflow = carry; + return is_zero; +} + +static int bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, + int *overflow) +{ + int carry = 0; + int i; + int is_zero = 1; + for (i = 1; i <= 31; i++) { + uint8_t digit = bcd_get_digit(a, i, invalid) - + bcd_get_digit(b, i, invalid) + carry; + is_zero &= (digit == 0); + if (digit & 0x80) { + carry = -1; + digit += 10; + } else { + carry = 0; + } + + bcd_put_digit(t, digit, i); + + if (unlikely(*invalid)) { + return -1; + } + } + + *overflow = carry; + return is_zero; +} + +uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) +{ + + int sgna = bcd_get_sgn(a); + int sgnb = bcd_get_sgn(b); + int invalid = (sgna == 0) || (sgnb == 0); + int overflow = 0; + int zero = 0; + uint32_t cr = 0; + ppc_avr_t result = { .u64 = { 0, 0 } }; + + if (!invalid) { + if (sgna == sgnb) { + result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); + zero = bcd_add_mag(&result, a, b, &invalid, &overflow); + cr = (sgna > 0) ? 4 : 8; + } else if (bcd_cmp_mag(a, b) > 0) { + result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); + zero = bcd_sub_mag(&result, a, b, &invalid, &overflow); + cr = (sgna > 0) ? 4 : 8; + } else { + result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgnb, ps); + zero = bcd_sub_mag(&result, b, a, &invalid, &overflow); + cr = (sgnb > 0) ? 4 : 8; + } + } + + if (unlikely(invalid)) { + result.u64[HI_IDX] = result.u64[LO_IDX] = -1; + cr = 1; + } else if (overflow) { + cr |= 1; + } else if (zero) { + cr = 2; + } + + *r = result; + + return cr; +} + +uint32_t helper_bcdsub(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) +{ + ppc_avr_t bcopy = *b; + int sgnb = bcd_get_sgn(b); + if (sgnb < 0) { + bcd_put_digit(&bcopy, BCD_PLUS_PREF_1, 0); + } else if (sgnb > 0) { + bcd_put_digit(&bcopy, BCD_NEG_PREF, 0); + } + /* else invalid ... defer to bcdadd code for proper handling */ + + return helper_bcdadd(r, a, &bcopy, ps); +} #undef VECTOR_FOR_INORDER_I #undef HI_IDX |