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Towards support full range of small ints in bytecode #311

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Towards support full range of small ints in bytecode #311

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17 changes: 17 additions & 0 deletions py/emitbc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,22 @@ STATIC void emit_write_byte_code_byte_byte(emit_t* emit, byte b1, uint b2) {
}

STATIC void emit_write_byte_code_uint(emit_t* emit, uint num) {
byte buf[10], *p = buf + sizeof(buf) - 1;
// We encode in little-ending order, but store in big-endian, to help decoding
while (num >= 0x80) {
*p-- = num & 0x7f;
num >>= 7;
}
// High bit == 0
*p = (byte)num;
//printf("Encoded %x using %d bytes\n", num, buf + sizeof(buf) - p);
byte* c = emit_get_cur_to_write_byte_code(emit, buf + sizeof(buf) - p);
while (p != buf + sizeof(buf) - 1) {
*c++ = *p++ | 0x80;
}
*c = *p;

#if 0
if (num <= 127) { // fits in 0x7f
// fit argument in single byte
byte* c = emit_get_cur_to_write_byte_code(emit, 1);
Expand All @@ -121,6 +137,7 @@ STATIC void emit_write_byte_code_uint(emit_t* emit, uint num) {
// larger numbers not implemented/supported
assert(0);
}
#endif
}

// integers (for small ints) are stored as 24 bits, in excess
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25 changes: 23 additions & 2 deletions py/vm.c
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Expand Up @@ -38,10 +38,31 @@ typedef enum {
UNWIND_JUMP,
} mp_unwind_reason_t;

#define DECODE_UINT do { unum = *ip++; if (unum > 127) { unum = ((unum & 0x3f) << 8) | (*ip++); } } while (0)
#if 0
uint decode_uint() {
uint val = 0;
do {
val = (val << 7) + (*ip & 0x7f);
} while ((*ip++ & 0x80) != 0);
}
#endif

//#define DECODE_UINT do { unum = *ip++; if (unum > 127) { unum = ((unum & 0x3f) << 8) | (*ip++); } } while (0)
#define DECODE_UINT { \
unum = 0; \
do { \
unum = (unum << 7) + (*ip & 0x7f); \
} while ((*ip++ & 0x80) != 0); \
}
#define DECODE_ULABEL do { unum = (ip[0] | (ip[1] << 8)); ip += 2; } while (0)
#define DECODE_SLABEL do { unum = (ip[0] | (ip[1] << 8)) - 0x8000; ip += 2; } while (0)
#define DECODE_QSTR do { qst = *ip++; if (qst > 127) { qst = ((qst & 0x3f) << 8) | (*ip++); } } while (0)
//#define DECODE_QSTR do { qst = *ip++; if (qst > 127) { qst = ((qst & 0x3f) << 8) | (*ip++); } } while (0)
#define DECODE_QSTR { \
qst = 0; \
do { \
qst = (qst << 7) + (*ip & 0x7f); \
} while ((*ip++ & 0x80) != 0); \
}
#define PUSH(val) *++sp = (val)
#define POP() (*sp--)
#define TOP() (*sp)
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