py/smallint: Introduce MP_SMALL_INT_BITS macro.

This adds a new MP_SMALL_INT_BITS macro that is a compile-time constant
that contains the number of bits available in an MP_SMALL_INT.

We can use this in place of the runtime function mp_small_int_bits().

Signed-off-by: David Lechner <david@pybricks.com>
This commit is contained in:
David Lechner 2022-03-23 14:29:52 -05:00 committed by Damien George
parent e7f6b9f4f7
commit 768879f999
2 changed files with 9 additions and 17 deletions

View File

@ -48,21 +48,6 @@
#define MPY_FEATURE_ARCH_DYNAMIC MPY_FEATURE_ARCH #define MPY_FEATURE_ARCH_DYNAMIC MPY_FEATURE_ARCH
#endif #endif
#if MICROPY_PERSISTENT_CODE_LOAD || (MICROPY_PERSISTENT_CODE_SAVE && !MICROPY_DYNAMIC_COMPILER)
// The bytecode will depend on the number of bits in a small-int, and
// this function computes that (could make it a fixed constant, but it
// would need to be defined in mpconfigport.h).
STATIC int mp_small_int_bits(void) {
mp_int_t i = MP_SMALL_INT_MAX;
int n = 1;
while (i != 0) {
i >>= 1;
++n;
}
return n;
}
#endif
typedef struct _bytecode_prelude_t { typedef struct _bytecode_prelude_t {
uint n_state; uint n_state;
uint n_exc_stack; uint n_exc_stack;
@ -420,7 +405,7 @@ mp_compiled_module_t mp_raw_code_load(mp_reader_t *reader, mp_module_context_t *
if (header[0] != 'M' if (header[0] != 'M'
|| header[1] != MPY_VERSION || header[1] != MPY_VERSION
|| MPY_FEATURE_DECODE_FLAGS(header[2]) != MPY_FEATURE_FLAGS || MPY_FEATURE_DECODE_FLAGS(header[2]) != MPY_FEATURE_FLAGS
|| header[3] > mp_small_int_bits()) { || header[3] > MP_SMALL_INT_BITS) {
mp_raise_ValueError(MP_ERROR_TEXT("incompatible .mpy file")); mp_raise_ValueError(MP_ERROR_TEXT("incompatible .mpy file"));
} }
if (MPY_FEATURE_DECODE_ARCH(header[2]) != MP_NATIVE_ARCH_NONE) { if (MPY_FEATURE_DECODE_ARCH(header[2]) != MP_NATIVE_ARCH_NONE) {
@ -609,7 +594,7 @@ void mp_raw_code_save(mp_compiled_module_t *cm, mp_print_t *print) {
#if MICROPY_DYNAMIC_COMPILER #if MICROPY_DYNAMIC_COMPILER
mp_dynamic_compiler.small_int_bits, mp_dynamic_compiler.small_int_bits,
#else #else
mp_small_int_bits(), MP_SMALL_INT_BITS,
#endif #endif
}; };
if (cm->has_native) { if (cm->has_native) {

View File

@ -61,6 +61,13 @@
#define MP_SMALL_INT_MAX ((mp_int_t)(~(MP_SMALL_INT_MIN))) #define MP_SMALL_INT_MAX ((mp_int_t)(~(MP_SMALL_INT_MIN)))
// https://stackoverflow.com/a/4589384/1976323
// Number of bits in inttype_MAX, or in any (1<<k)-1 where 0 <= k < 2040
#define MP_IMAX_BITS(m) ((m) / ((m) % 255 + 1) / 255 % 255 * 8 + 7 - 86 / ((m) % 255 + 12))
// The number of bits in a MP_SMALL_INT including the sign bit.
#define MP_SMALL_INT_BITS (MP_IMAX_BITS(MP_SMALL_INT_MAX) + 1)
bool mp_small_int_mul_overflow(mp_int_t x, mp_int_t y); bool mp_small_int_mul_overflow(mp_int_t x, mp_int_t y);
mp_int_t mp_small_int_modulo(mp_int_t dividend, mp_int_t divisor); mp_int_t mp_small_int_modulo(mp_int_t dividend, mp_int_t divisor);
mp_int_t mp_small_int_floor_divide(mp_int_t num, mp_int_t denom); mp_int_t mp_small_int_floor_divide(mp_int_t num, mp_int_t denom);