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author | Mike Pall <mike> | 2022-03-08 19:44:10 +0100 |
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committer | Mike Pall <mike> | 2022-03-08 19:44:10 +0100 |
commit | 96d6d5032098ea9f0002165394a8774dcaa0c0ce (patch) | |
tree | 84712e02c1452d8f0c48a6f506a9aa1ebe0f4a32 /src/lj_vmmath.c | |
parent | aa0550e3f0999cc6ef62f7ef80493ebef8c9a2f7 (diff) | |
download | luajit-96d6d5032098ea9f0002165394a8774dcaa0c0ce.tar.gz luajit-96d6d5032098ea9f0002165394a8774dcaa0c0ce.tar.bz2 luajit-96d6d5032098ea9f0002165394a8774dcaa0c0ce.zip |
Revert to trival pow() optimizations to prevent inaccuracies.
Diffstat (limited to 'src/lj_vmmath.c')
-rw-r--r-- | src/lj_vmmath.c | 44 |
1 files changed, 2 insertions, 42 deletions
diff --git a/src/lj_vmmath.c b/src/lj_vmmath.c index fa0de922..b6cc60ba 100644 --- a/src/lj_vmmath.c +++ b/src/lj_vmmath.c | |||
@@ -30,52 +30,12 @@ LJ_FUNCA double lj_wrap_sinh(double x) { return sinh(x); } | |||
30 | LJ_FUNCA double lj_wrap_cosh(double x) { return cosh(x); } | 30 | LJ_FUNCA double lj_wrap_cosh(double x) { return cosh(x); } |
31 | LJ_FUNCA double lj_wrap_tanh(double x) { return tanh(x); } | 31 | LJ_FUNCA double lj_wrap_tanh(double x) { return tanh(x); } |
32 | LJ_FUNCA double lj_wrap_atan2(double x, double y) { return atan2(x, y); } | 32 | LJ_FUNCA double lj_wrap_atan2(double x, double y) { return atan2(x, y); } |
33 | LJ_FUNCA double lj_wrap_pow(double x, double y) { return pow(x, y); } | ||
33 | LJ_FUNCA double lj_wrap_fmod(double x, double y) { return fmod(x, y); } | 34 | LJ_FUNCA double lj_wrap_fmod(double x, double y) { return fmod(x, y); } |
34 | #endif | 35 | #endif |
35 | 36 | ||
36 | /* -- Helper functions ---------------------------------------------------- */ | 37 | /* -- Helper functions ---------------------------------------------------- */ |
37 | 38 | ||
38 | /* Unsigned x^k. */ | ||
39 | static double lj_vm_powui(double x, uint32_t k) | ||
40 | { | ||
41 | double y; | ||
42 | lj_assertX(k != 0, "pow with zero exponent"); | ||
43 | for (; (k & 1) == 0; k >>= 1) x *= x; | ||
44 | y = x; | ||
45 | if ((k >>= 1) != 0) { | ||
46 | for (;;) { | ||
47 | x *= x; | ||
48 | if (k == 1) break; | ||
49 | if (k & 1) y *= x; | ||
50 | k >>= 1; | ||
51 | } | ||
52 | y *= x; | ||
53 | } | ||
54 | return y; | ||
55 | } | ||
56 | |||
57 | /* Signed x^k. */ | ||
58 | double lj_vm_powi(double x, int32_t k) | ||
59 | { | ||
60 | if (k > 1) | ||
61 | return lj_vm_powui(x, (uint32_t)k); | ||
62 | else if (k == 1) | ||
63 | return x; | ||
64 | else if (k == 0) | ||
65 | return 1.0; | ||
66 | else | ||
67 | return 1.0 / lj_vm_powui(x, (uint32_t)-k); | ||
68 | } | ||
69 | |||
70 | double lj_vm_pow(double x, double y) | ||
71 | { | ||
72 | int32_t k = lj_num2int(y); | ||
73 | if ((k >= -65536 && k <= 65536) && y == (double)k) | ||
74 | return lj_vm_powi(x, k); | ||
75 | else | ||
76 | return pow(x, y); | ||
77 | } | ||
78 | |||
79 | double lj_vm_foldarith(double x, double y, int op) | 39 | double lj_vm_foldarith(double x, double y, int op) |
80 | { | 40 | { |
81 | switch (op) { | 41 | switch (op) { |
@@ -84,7 +44,7 @@ double lj_vm_foldarith(double x, double y, int op) | |||
84 | case IR_MUL - IR_ADD: return x*y; break; | 44 | case IR_MUL - IR_ADD: return x*y; break; |
85 | case IR_DIV - IR_ADD: return x/y; break; | 45 | case IR_DIV - IR_ADD: return x/y; break; |
86 | case IR_MOD - IR_ADD: return x-lj_vm_floor(x/y)*y; break; | 46 | case IR_MOD - IR_ADD: return x-lj_vm_floor(x/y)*y; break; |
87 | case IR_POW - IR_ADD: return lj_vm_pow(x, y); break; | 47 | case IR_POW - IR_ADD: return pow(x, y); break; |
88 | case IR_NEG - IR_ADD: return -x; break; | 48 | case IR_NEG - IR_ADD: return -x; break; |
89 | case IR_ABS - IR_ADD: return fabs(x); break; | 49 | case IR_ABS - IR_ADD: return fabs(x); break; |
90 | #if LJ_HASJIT | 50 | #if LJ_HASJIT |