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authorMike Pall <mike>2022-03-08 19:44:10 +0100
committerMike Pall <mike>2022-03-08 19:44:10 +0100
commit96d6d5032098ea9f0002165394a8774dcaa0c0ce (patch)
tree84712e02c1452d8f0c48a6f506a9aa1ebe0f4a32 /src/lj_vmmath.c
parentaa0550e3f0999cc6ef62f7ef80493ebef8c9a2f7 (diff)
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Revert to trival pow() optimizations to prevent inaccuracies.
Diffstat (limited to 'src/lj_vmmath.c')
-rw-r--r--src/lj_vmmath.c44
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); }
30LJ_FUNCA double lj_wrap_cosh(double x) { return cosh(x); } 30LJ_FUNCA double lj_wrap_cosh(double x) { return cosh(x); }
31LJ_FUNCA double lj_wrap_tanh(double x) { return tanh(x); } 31LJ_FUNCA double lj_wrap_tanh(double x) { return tanh(x); }
32LJ_FUNCA double lj_wrap_atan2(double x, double y) { return atan2(x, y); } 32LJ_FUNCA double lj_wrap_atan2(double x, double y) { return atan2(x, y); }
33LJ_FUNCA double lj_wrap_pow(double x, double y) { return pow(x, y); }
33LJ_FUNCA double lj_wrap_fmod(double x, double y) { return fmod(x, y); } 34LJ_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. */
39static 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. */
58double 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
70double 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
79double lj_vm_foldarith(double x, double y, int op) 39double 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