ab9a98602
Denys Vlasenko
2018-12-26
Subject
bc: simple speedups
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miscutils/bc.c+28 -1
| @@ -3439,17 +3439,38 @@ static void bc_parse_push(char i) | |
| static void bc_parse_pushName(char *name) | |
| { | |
| + | #if 1 |
| + | BcVec *code = &G.prs.func->code; |
| + | size_t pos = code->len; |
| + | size_t len = strlen(name) + 1; |
| + | |
| + | bc_vec_expand(code, pos + len); |
| + | strcpy(code->v + pos, name); |
| + | code->len = pos + len; |
| + | #else |
| + | // Smaller code, but way slow: |
| do { | |
| bc_parse_push(*name); | |
| } while (*name++); | |
| + | #endif |
| } | |
| + | // Indexes < 0xfc are encoded verbatim, else first byte is |
| + | // 0xfc, 0xfd, 0xfe or 0xff, encoding "1..4 bytes", |
| + | // followed by that many bytes, lsb first. |
| + | // (The above describes 32-bit case). |
| + | #define SMALL_INDEX_LIMIT (0x100 - sizeof(size_t)) |
| + | |
| static void bc_parse_pushIndex(size_t idx) | |
| { | |
| size_t mask; | |
| unsigned amt; | |
| dbg_lex("%s:%d pushing index %zd", __func__, __LINE__, idx); | |
| + | if (idx < SMALL_INDEX_LIMIT) { |
| + | goto push_idx; |
| + | } |
| + | |
| mask = ((size_t)0xff) << (sizeof(idx) * 8 - 8); | |
| amt = sizeof(idx); | |
| do { | |
| @@ -3458,9 +3479,10 @@ static void bc_parse_pushIndex(size_t idx) | |
| amt--; | |
| } while (amt != 0); | |
| - | bc_parse_push(amt); |
| + | bc_parse_push(SMALL_INDEX_LIMIT + amt); |
| while (idx != 0) { | |
| + | push_idx: |
| bc_parse_push((unsigned char)idx); | |
| idx >>= 8; | |
| } | |
| @@ -5257,6 +5279,11 @@ static size_t bc_program_index(char *code, size_t *bgn) | |
| size_t res; | |
| amt = *bytes++; | |
| + | if (amt < SMALL_INDEX_LIMIT) { |
| + | *bgn += 1; |
| + | return amt; |
| + | } |
| + | amt -= SMALL_INDEX_LIMIT; |
| *bgn += amt + 1; | |
| amt *= 8; | |