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Use explicit 32-bit integers in random number system functions (issue #661). 

This simplifies the code by making it independent of the size of 'long', and
fixes the behaviour of urandom_range when the upper limit is > 0x7fffffff.
This commit is contained in:
Martin Whitaker 2022-04-03 19:45:44 +01:00
parent d480c4d7d0
commit 94e09ec473
1 changed files with 82 additions and 100 deletions
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182
vpi/sys_random.c
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2000-2021 Stephen Williams (steve@icarus.com)
* Copyright (c) 2000-2022 Stephen Williams (steve@icarus.com)
*
* This source code is free software; you can redistribute it
* and/or modify it in source code form under the terms of the GNU
@ -25,34 +25,35 @@
# include <math.h>
# include <limits.h>
#if ULONG_MAX > 4294967295UL
# define UNIFORM_MAX INT_MAX
# define UNIFORM_MIN INT_MIN
#else
# define UNIFORM_MAX LONG_MAX
# define UNIFORM_MIN LONG_MIN
#endif
/*
* The following code is largely copied from the IEEE standard (section 17.9.3
* in IEEE 1364-2005, Annex N in IEEE 1800-2017). The code in the IEEE standard
* predates the widespread availability of 64-bit processors, so assumes 'long'
* is a 32 bit value (https://accellera.mantishub.io/view.php?id=1136). So we
* replace 'long' with 'int32_t' to ensure correct and consistent behaviour
* regardless of how the code is built.
*/
static double uniform(long *seed, long start, long end);
static double normal(long *seed, long mean, long deviation);
static double exponential(long *seed, long mean);
static long poisson(long *seed, long mean);
static double chi_square(long *seed, long deg_of_free);
static double t(long *seed, long deg_of_free);
static double erlangian(long *seed, long k, long mean);
static double uniform(int32_t *seed, int32_t start, int32_t end);
static double normal(int32_t *seed, int32_t mean, int32_t deviation);
static double exponential(int32_t *seed, int32_t mean);
static int32_t poisson(int32_t *seed, int32_t mean);
static double chi_square(int32_t *seed, int32_t deg_of_free);
static double t(int32_t *seed, int32_t deg_of_free);
static double erlangian(int32_t *seed, int32_t k, int32_t mean);
static long rtl_dist_chi_square(long *seed, long df)
static int32_t rtl_dist_chi_square(int32_t *seed, int32_t df)
{
double r;
long i;
int32_t i;
if (df > 0) {
r = chi_square(seed, df);
if (r >= 0) {
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
} else {
r = -r;
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
i = -i;
}
} else {
@ -64,18 +65,18 @@ static long rtl_dist_chi_square(long *seed, long df)
return i;
}
static long rtl_dist_erlang(long *seed, long k, long mean)
static int32_t rtl_dist_erlang(int32_t *seed, int32_t k, int32_t mean)
{
double r;
long i;
int32_t i;
if (k > 0) {
r = erlangian(seed, k, mean);
if (r >= 0) {
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
} else {
r = -r;
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
i = -i;
}
} else {
@ -87,18 +88,18 @@ static long rtl_dist_erlang(long *seed, long k, long mean)
return i;
}
static long rtl_dist_exponential(long *seed, long mean)
static int32_t rtl_dist_exponential(int32_t *seed, int32_t mean)
{
double r;
long i;
int32_t i;
if (mean > 0) {
r = exponential(seed, mean);
if (r >= 0) {
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
} else {
r = -r;
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
i = -i;
}
} else {
@ -110,26 +111,26 @@ static long rtl_dist_exponential(long *seed, long mean)
return i;
}
static long rtl_dist_normal(long *seed, long mean, long sd)
static int32_t rtl_dist_normal(int32_t *seed, int32_t mean, int32_t sd)
{
double r;
long i;
int32_t i;
r = normal(seed, mean, sd);
if (r >= 0) {
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
} else {
r = -r;
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
i = -i;
}
return i;
}
static long rtl_dist_poisson(long *seed, long mean)
static int32_t rtl_dist_poisson(int32_t *seed, int32_t mean)
{
long i;
int32_t i;
if (mean > 0) {
i = poisson(seed, mean);
@ -142,18 +143,18 @@ static long rtl_dist_poisson(long *seed, long mean)
return i;
}
static long rtl_dist_t(long *seed, long df)
static int32_t rtl_dist_t(int32_t *seed, int32_t df)
{
double r;
long i;
int32_t i;
if (df > 0) {
r = t(seed, df);
if (r >= 0) {
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
} else {
r = -r;
i = (long) (r + 0.5);
i = (int32_t) (r + 0.5);
i = -i;
}
} else {
@ -165,36 +166,30 @@ static long rtl_dist_t(long *seed, long df)
return i;
}
/* copied from IEEE1364-2001, with slight modifications for 64bit machines. */
static long rtl_dist_uniform(long *seed, long start, long end)
static int32_t rtl_dist_uniform(int32_t *seed, int32_t start, int32_t end)
{
double r;
long i;
int32_t i;
if (start >= end) return(start);
if (start >= end) return start;
/* NOTE: The cast of r to i can overflow and generate strange
values, so cast to unsigned long first. This eliminates
the underflow and gets the twos complement value. That in
turn can be cast to the long value that is expected. */
if (end != UNIFORM_MAX) {
if (end != INT32_MAX) {
end++;
r = uniform(seed, start, end);
if (r >= 0) {
i = (unsigned long) r;
i = (int32_t) r;
} else {
i = - ( (unsigned long) (-(r - 1)) );
i = (int32_t) (r - 1);
}
if (i < start) i = start;
if (i >= end) i = end - 1;
} else if (start != UNIFORM_MIN) {
} else if (start != INT32_MIN) {
start--;
r = uniform( seed, start, end) + 1.0;
r = uniform(seed, start, end) + 1.0;
if (r >= 0) {
i = (unsigned long) r;
i = (int32_t) r;
} else {
i = - ( (unsigned long) (-(r - 1)) );
i = (int32_t) (r - 1);
}
if (i <= start) i = start + 1;
if (i > end) i = end;
@ -203,25 +198,20 @@ static long rtl_dist_uniform(long *seed, long start, long end)
r = r * 4294967296.0 - 2147483648.0;
if (r >= 0) {
i = (unsigned long) r;
i = (int32_t) r;
} else {
/* At least some compilers will notice that (r-1)
is <0 when castling to unsigned long and
replace the result with a zero. This causes
much wrongness, so do the casting to the
positive version and invert it back. */
i = - ( (unsigned long) (-(r - 1)) );
i = (int32_t) (r - 1);
}
}
return i;
}
static double uniform(long *seed, long start, long end )
static double uniform(int32_t *seed, int32_t start, int32_t end)
{
double d = 0.00000011920928955078125;
double a, b, c;
unsigned long oldseed, newseed;
uint32_t oldseed, newseed;
oldseed = *seed;
if (oldseed == 0)
@ -243,15 +233,8 @@ static double uniform(long *seed, long start, long end )
*/
newseed = 69069 * oldseed + 1;
/* Emulate a 32-bit unsigned long, even if the native machine
* uses wider words.
*/
#if ULONG_MAX > 4294967295UL
newseed = newseed & 4294967295UL;
#endif
*seed = newseed;
#if 0
/* Cadence-donated conversion from unsigned int to double */
{
@ -265,14 +248,13 @@ static double uniform(long *seed, long start, long end )
c = 1.0 + (newseed >> 9) * 0.00000011920928955078125;
#endif
c = c + (c*d);
c = ((b - a) * (c - 1.0)) + a;
return c;
}
static double normal(long *seed, long mean, long deviation)
static double normal(int32_t *seed, int32_t mean, int32_t deviation)
{
double v1, v2, s;
@ -289,7 +271,7 @@ static double normal(long *seed, long mean, long deviation)
return s * v1 + v2;
}
static double exponential(long *seed, long mean)
static double exponential(int32_t *seed, int32_t mean)
{
double n;
@ -301,9 +283,9 @@ static double exponential(long *seed, long mean)
return n;
}
static long poisson(long *seed, long mean)
static int32_t poisson(int32_t *seed, int32_t mean)
{
long n;
int32_t n;
double p, q;
n = 0;
@ -318,10 +300,10 @@ static long poisson(long *seed, long mean)
return n;
}
static double chi_square(long *seed, long deg_of_free)
static double chi_square(int32_t *seed, int32_t deg_of_free)
{
double x;
long k;
int32_t k;
if (deg_of_free % 2) {
x = normal(seed, 0, 1);
@ -336,7 +318,7 @@ static double chi_square(long *seed, long deg_of_free)
return x;
}
static double t( long *seed, long deg_of_free)
static double t( int32_t *seed, int32_t deg_of_free)
{
double x, chi2, dv, root;
@ -348,10 +330,10 @@ static double t( long *seed, long deg_of_free)
return x;
}
static double erlangian(long *seed, long k, long mean)
static double erlangian(int32_t *seed, int32_t k, int32_t mean)
{
double x, a, b;
long i;
int32_t i;
x = 1.0;
for (i = 1; i <= k; i++) {
@ -533,8 +515,8 @@ static PLI_INT32 sys_random_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed = 0;
s_vpi_value val;
static long i_seed = 0;
long a_seed;
static int32_t i_seed = 0;
int32_t a_seed;
(void)name; /* Parameter is not used. */
@ -599,16 +581,16 @@ static PLI_INT32 sys_urandom_range_compiletf(ICARUS_VPI_CONST PLI_BYTE8 *name)
}
/* From SystemVerilog. */
static unsigned long urandom(long *seed, unsigned long max, unsigned long min)
static uint32_t urandom(int32_t *seed, uint32_t max, uint32_t min)
{
static long i_seed = 0;
unsigned long result;
long max_i, min_i;
static int32_t i_seed = 0;
int32_t max_i, min_i;
uint32_t result;
max_i = max + INT_MIN;
min_i = min + INT_MIN;
max_i = max + INT32_MIN;
min_i = min + INT32_MIN;
if (seed != 0) i_seed = *seed;
result = rtl_dist_uniform(&i_seed, min_i, max_i) - INT_MIN;
result = (uint32_t)rtl_dist_uniform(&i_seed, min_i, max_i) - INT32_MIN;
if (seed != 0) *seed = i_seed;
return result;
}
@ -618,7 +600,7 @@ static PLI_INT32 sys_urandom_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed = 0;
s_vpi_value val;
long i_seed;
int32_t i_seed;
(void)name; /* Parameter is not used. */
@ -636,9 +618,9 @@ static PLI_INT32 sys_urandom_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
/* Calculate and return the result. */
if (seed) {
val.value.integer = urandom(&i_seed, UINT_MAX, 0);
val.value.integer = urandom(&i_seed, UINT32_MAX, 0);
} else {
val.value.integer = urandom(0, UINT_MAX, 0);
val.value.integer = urandom(0, UINT32_MAX, 0);
}
vpi_put_value(callh, &val, 0, vpiNoDelay);
@ -656,7 +638,7 @@ static PLI_INT32 sys_urandom_range_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, maxval, minval;
s_vpi_value val;
unsigned long i_maxval, i_minval;
uint32_t i_maxval, i_minval;
(void)name; /* Parameter is not used. */
@ -681,7 +663,7 @@ static PLI_INT32 sys_urandom_range_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
/* Swap the two arguments if they are out of order. */
if (i_minval > i_maxval) {
unsigned long tmp = i_minval;
uint32_t tmp = i_minval;
i_minval = i_maxval;
i_maxval = tmp;
}
@ -696,7 +678,7 @@ static PLI_INT32 sys_dist_uniform_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, start, end;
s_vpi_value val;
long i_seed, i_start, i_end;
int32_t i_seed, i_start, i_end;
(void)name; /* Parameter is not used. */
@ -733,7 +715,7 @@ static PLI_INT32 sys_dist_normal_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, mean, sd;
s_vpi_value val;
long i_seed, i_mean, i_sd;
int32_t i_seed, i_mean, i_sd;
(void)name; /* Parameter is not used. */
@ -770,7 +752,7 @@ static PLI_INT32 sys_dist_exponential_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, mean;
s_vpi_value val;
long i_seed, i_mean;
int32_t i_seed, i_mean;
(void)name; /* Parameter is not used. */
@ -803,7 +785,7 @@ static PLI_INT32 sys_dist_poisson_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, mean;
s_vpi_value val;
long i_seed, i_mean;
int32_t i_seed, i_mean;
(void)name; /* Parameter is not used. */
@ -836,7 +818,7 @@ static PLI_INT32 sys_dist_chi_square_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, df;
s_vpi_value val;
long i_seed, i_df;
int32_t i_seed, i_df;
(void)name; /* Parameter is not used. */
@ -869,7 +851,7 @@ static PLI_INT32 sys_dist_t_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, df;
s_vpi_value val;
long i_seed, i_df;
int32_t i_seed, i_df;
(void)name; /* Parameter is not used. */
@ -902,7 +884,7 @@ static PLI_INT32 sys_dist_erlang_calltf(ICARUS_VPI_CONST PLI_BYTE8 *name)
{
vpiHandle callh, argv, seed, k, mean;
s_vpi_value val;
long i_seed, i_k, i_mean;
int32_t i_seed, i_k, i_mean;
(void)name; /* Parameter is not used. */