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parse: Implement hacky way to handle full range of small ints. #313

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parse: Implement hacky way to handle full range of small ints. #313

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14 changes: 13 additions & 1 deletion py/compile.c
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Expand Up @@ -148,6 +148,7 @@ mp_parse_node_t fold_constants(mp_parse_node_t pn) {
break;

case PN_factor_2:
// TODO: Handle specially incoded MP_PARSE_NODE_INT here too?
if (MP_PARSE_NODE_IS_SMALL_INT(pns->nodes[1])) {
machine_int_t arg = MP_PARSE_NODE_LEAF_ARG(pns->nodes[1]);
if (MP_PARSE_NODE_IS_TOKEN_KIND(pns->nodes[0], MP_TOKEN_OP_PLUS)) {
Expand Down Expand Up @@ -2519,7 +2520,18 @@ void compile_node(compiler_t *comp, mp_parse_node_t pn) {
switch (MP_PARSE_NODE_LEAF_KIND(pn)) {
case MP_PARSE_NODE_ID: EMIT_ARG(load_id, arg); break;
case MP_PARSE_NODE_SMALL_INT: EMIT_ARG(load_const_small_int, arg); break;
case MP_PARSE_NODE_INTEGER: EMIT_ARG(load_const_int, arg); break;
case MP_PARSE_NODE_INTEGER: {
const char *p = qstr_str(arg);
if (*p == 0) {
// Specially encoded full-range small int
machine_int_t val;
memcpy(&val, p + 1, sizeof(val));
EMIT_ARG(load_const_small_int, val);
} else {
EMIT_ARG(load_const_int, arg);
}
break;
}
case MP_PARSE_NODE_DECIMAL: EMIT_ARG(load_const_dec, arg); break;
case MP_PARSE_NODE_STRING: EMIT_ARG(load_const_str, arg, false); break;
case MP_PARSE_NODE_BYTES: EMIT_ARG(load_const_str, arg, true); break;
Expand Down
14 changes: 12 additions & 2 deletions py/parse.c
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Expand Up @@ -11,6 +11,7 @@
#include "qstr.h"
#include "lexer.h"
#include "parse.h"
#include "obj.h"

#define RULE_ACT_KIND_MASK (0xf0)
#define RULE_ACT_ARG_MASK (0x0f)
Expand Down Expand Up @@ -279,8 +280,17 @@ STATIC void push_result_token(parser_t *parser, const mp_lexer_t *lex) {
}
if (dec) {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_DECIMAL, qstr_from_strn(str, len));
} else if (small_int && !overflow && MP_PARSE_FITS_SMALL_INT(int_val)) {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, int_val);
} else if (small_int && !overflow && MP_OBJ_FITS_SMALL_INT(int_val)) {
if (MP_PARSE_FITS_SMALL_INT(int_val)) {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_SMALL_INT, int_val);
} else {
// If value doesn't fit into parser's small int, but fits into
// object small int, encode it in special form of MP_PARSE_NODE_INTEGER
char buf[BYTES_PER_WORD + 1];
buf[0] = 0;
memcpy(buf + 1, &int_val, sizeof(int_val));
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_INTEGER, qstr_from_strn(buf, sizeof(buf)));
}
} else {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_INTEGER, qstr_from_strn(str, len));
}
Expand Down
25 changes: 25 additions & 0 deletions tests/basics/int-small.py
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@@ -1,5 +1,30 @@
# This tests small int range for 32-bit machine

# Small ints are variable-length encoded in MicroPython, so first
# test that encoding works as expected.

print(0)
print(1)
print(-1)
# Value is split in 7-bit "subwords", and taking into account that all
# ints in Python are signed, there're 6 bits of magnitude. So, around 2^6
# there's "turning point"
print(63)
print(64)
print(65)
print(-63)
print(-64)
print(-65)
# Maximum values of small ints on 32-bit platform
print(1073741823)
# Per python semantics, lexical integer is without a sign (i.e. positive)
# and '-' is unary minus operation applied to it. That's why -1073741824
# (min two-complement's negative value) is not allowed. To fix this,
# see compile.c:fold_constants()
print(-1073741823)

# Operations tests

a = 0x3fffff
print(a)
a *= 0x10
Expand Down