Change division and modulus to use euclidean division, plus fix up a few

integer bugs
This commit is contained in:
Bruce Hill 2024-08-16 14:24:20 -04:00
parent 04714e00d7
commit bac188ce07
4 changed files with 86 additions and 25 deletions

View File

@ -152,17 +152,20 @@ public Int_t Int$slow_times(Int_t x, Int_t y) {
return Int$from_mpz(result);
}
public Int_t Int$slow_divided_by(Int_t x, Int_t y) {
mpz_t result;
mpz_init_set_int(result, x);
if (y.small & 1) {
mpz_t y_mpz;
mpz_init_set_si(y_mpz, y.small >> 2);
mpz_cdiv_q(result, result, y_mpz);
} else {
mpz_cdiv_q(result, result, *y.big);
public Int_t Int$slow_divided_by(Int_t dividend, Int_t divisor) {
// Euclidean division, see: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/divmodnote-letter.pdf
mpz_t quotient, remainder;
mpz_init_set_int(quotient, dividend);
mpz_init_set_int(remainder, divisor);
mpz_tdiv_qr(quotient, remainder, quotient, remainder);
if (mpz_sgn(remainder) < 0) {
bool d_positive = __builtin_expect(divisor.small & 1, 1) ? divisor.small > 0x1 : mpz_sgn(*divisor.big) > 0;
if (d_positive)
mpz_sub_ui(quotient, quotient, 1);
else
mpz_add_ui(quotient, quotient, 1);
}
return Int$from_mpz(result);
return Int$from_mpz(quotient);
}
public Int_t Int$slow_modulo(Int_t x, Int_t modulus)
@ -359,7 +362,7 @@ public const TypeInfo $Int = {
} \
public CORD KindOfInt ## $format(c_type i, Int_t digits_int) { \
int64_t digits = Int_to_Int64(digits_int, false); \
return CORD_asprintf("%0*" fmt, (int)digits, i); \
return CORD_asprintf("%0*ld", (int)digits, (int64_t)i); \
} \
public CORD KindOfInt ## $hex(c_type i, Int_t digits_int, bool uppercase, bool prefix) { \
int64_t digits = Int_to_Int64(digits_int, false); \
@ -427,7 +430,7 @@ public const TypeInfo $Int = {
.CustomInfo={.compare=(void*)KindOfInt##$compare, .as_text=(void*)KindOfInt##$as_text}, \
};
DEFINE_INT_TYPE(int64_t, Int64, "ld", INT64_MIN, INT64_MAX);
DEFINE_INT_TYPE(int64_t, Int64, "ld_i64", INT64_MIN, INT64_MAX);
DEFINE_INT_TYPE(int32_t, Int32, "d_i32", INT32_MIN, INT32_MAX);
DEFINE_INT_TYPE(int16_t, Int16, "d_i16", INT16_MIN, INT16_MAX);
DEFINE_INT_TYPE(int8_t, Int8, "d_i8", INT8_MIN, INT8_MAX);

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@ -35,7 +35,26 @@
Range_t type_name ## $to(c_type from, c_type to); \
c_type type_name ## $from_text(CORD text, CORD *the_rest); \
extern const c_type type_name ## $min, type_name##$max; \
extern const TypeInfo $ ## type_name;
extern const TypeInfo $ ## type_name; \
static inline c_type type_name ## $divided_by(c_type D, c_type d) { \
c_type q = D/d, r = D%d; \
if (r < 0) { \
if (d > 0) q = q-1; \
else q = q+1; \
} \
return q; \
} \
static inline c_type type_name ## $modulo(c_type D, c_type d) { \
c_type r = D%d; \
if (r < 0) { \
if (d > 0) r = r + d; \
else r = r - d; \
} \
return r; \
} \
static inline c_type type_name ## $modulo1(c_type D, c_type d) { \
return type_name ## $modulo(D-1, d) + 1; \
}
DEFINE_INT_TYPE(int64_t, Int64);
DEFINE_INT_TYPE(int32_t, Int32);
@ -128,27 +147,47 @@ static inline Int_t Int$times(Int_t x, Int_t y) {
static inline Int_t Int$divided_by(Int_t x, Int_t y) {
if (__builtin_expect(((x.small & y.small) & 1) != 0, 1)) {
const int64_t z = ((x.small>>1) / (y.small>>1)) << 2;
if (__builtin_expect(z == (int32_t)z, 1))
return (Int_t){.small=z|1};
// Euclidean division, see: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/divmodnote-letter.pdf
const int64_t D = (x.small>>2);
const int64_t d = (y.small>>2);
int64_t q = D/d;
int64_t r = D%d;
if (r < 0) {
if (d > 0) q = q-1;
else q = q+1;
}
if (__builtin_expect(q == (int32_t)q, 1))
return (Int_t){.small=(q<<2)|1};
}
return Int$slow_divided_by(x, y);
}
static inline Int_t Int$modulo(Int_t x, Int_t y) {
if (__builtin_expect(((x.small & y.small) & 1) != 0, 1)) {
int64_t mod = (x.small>>2) % (y.small>>2);
if (mod < 0) mod += (y.small>>2);
return (Int_t){.small=(mod<<2)+1};
// Euclidean modulus, see: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/divmodnote-letter.pdf
const int64_t D = (x.small>>2);
const int64_t d = (y.small>>2);
int64_t r = D%d;
if (r < 0) {
if (d > 0) r = r + d;
else r = r - d;
}
return (Int_t){.small=(r<<2)|1};
}
return Int$slow_modulo(x, y);
}
static inline Int_t Int$modulo1(Int_t x, Int_t y) {
if (__builtin_expect(((x.small & y.small) & 1) != 0, 1)) {
int64_t mod = ((x.small>>2)-1) % (y.small>>2);
if (mod < 0) mod += (y.small>>2);
return (Int_t){.small=((mod+1)<<2)+1};
// Euclidean modulus, see: https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/divmodnote-letter.pdf
const int64_t D = (x.small>>2)-1;
const int64_t d = (y.small>>2);
int64_t r = D%d;
if (r < 0) {
if (d > 0) r = r + d;
else r = r - d;
}
return (Int_t){.small=((r+1)<<2)|1};
}
return Int$slow_modulo1(x, y);
}

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@ -115,13 +115,16 @@ env_t *new_compilation_unit(CORD *libname)
{"format", "Int64$format", "func(i:Int64, digits=0)->Text"},
{"hex", "Int64$hex", "func(i:Int64, digits=0, uppercase=yes, prefix=yes)->Text"},
{"octal", "Int64$octal", "func(i:Int64, digits=0, prefix=yes)->Text"},
{"random", "Int64$random", "func(min=-0x8000000000000000, max=0x7FFFFFFFFFFFFFFF)->Int64"},
{"random", "Int64$random", "func(min=-0x8000000000000000_i64, max=0x7FFFFFFFFFFFFFFF_i64)->Int64"},
{"from_text", "Int64$from_text", "func(text:Text, the_rest=!&Text)->Int64"},
{"bits", "Int64$bits", "func(x:Int64)->[Bool]"},
{"abs", "labs", "func(i:Int64)->Int64"},
{"min", "Int64$min", "Int64"},
{"max", "Int64$max", "Int64"},
{"to", "Int64$to", "func(from:Int64,to:Int64)->Range"},
{"divided_by", "Int64$divided_by", "func(x:Int64,y:Int64)->Int64"},
{"modulo", "Int64$modulo", "func(x:Int64,y:Int64)->Int64"},
{"modulo1", "Int64$modulo1", "func(x:Int64,y:Int64)->Int64"},
)},
{"Int32", Type(IntType, .bits=32), "Int32_t", "$Int32", TypedArray(ns_entry_t,
{"format", "Int32$format", "func(i:Int32, digits=0)->Text"},
@ -134,6 +137,9 @@ env_t *new_compilation_unit(CORD *libname)
{"min", "Int32$min", "Int32"},
{"max", "Int32$max", "Int32"},
{"to", "Int32$to", "func(from:Int32,to:Int32)->Range"},
{"divided_by", "Int32$divided_by", "func(x:Int32,y:Int32)->Int32"},
{"modulo", "Int32$modulo", "func(x:Int32,y:Int32)->Int32"},
{"modulo1", "Int32$modulo1", "func(x:Int32,y:Int32)->Int32"},
)},
{"Int16", Type(IntType, .bits=16), "Int16_t", "$Int16", TypedArray(ns_entry_t,
{"format", "Int16$format", "func(i:Int16, digits=0)->Text"},
@ -146,6 +152,9 @@ env_t *new_compilation_unit(CORD *libname)
{"min", "Int16$min", "Int16"},
{"max", "Int16$max", "Int16"},
{"to", "Int16$to", "func(from:Int16,to:Int16)->Range"},
{"divided_by", "Int16$divided_by", "func(x:Int16,y:Int16)->Int16"},
{"modulo", "Int16$modulo", "func(x:Int16,y:Int16)->Int16"},
{"modulo1", "Int16$modulo1", "func(x:Int16,y:Int16)->Int16"},
)},
{"Int8", Type(IntType, .bits=8), "Int8_t", "$Int8", TypedArray(ns_entry_t,
{"format", "Int8$format", "func(i:Int8, digits=0)->Text"},
@ -158,6 +167,9 @@ env_t *new_compilation_unit(CORD *libname)
{"min", "Int8$min", "Int8"},
{"max", "Int8$max", "Int8"},
{"to", "Int8$to", "func(from:Int8,to:Int8)->Range"},
{"divided_by", "Int8$divided_by", "func(x:Int8,y:Int8)->Int8"},
{"modulo", "Int8$modulo", "func(x:Int8,y:Int8)->Int8"},
{"modulo1", "Int8$modulo1", "func(x:Int8,y:Int8)->Int8"},
)},
#define C(name) {#name, "M_"#name, "Num"}
#define F(name) {#name, #name, "func(n:Num)->Num"}

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@ -42,9 +42,9 @@ func main():
>> Int.random(1, 100)
>> Int64.min
= -9223372036854775808
= -9223372036854775808_i64
>> Int64.max
= 9223372036854775807
= 9223372036854775807_i64
>> 123_i32:hex()
@ -75,3 +75,10 @@ func main():
>> super_big + 1
= 10000000000000000000000
do:
for in 20:
>> n := Int.random(-999999, 999999)
>> d := Int.random(-999, 999)
//! n={n}, d={d}:
>> (n/d)*d + (n mod d) == n
= yes