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From Lua 5.2: Add math.log(x, base).

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This commit is contained in:
Mike Pall
2012-10-07 15:47:11 +02:00
parent 0d62e2e1ab
commit 0561a56938
8 changed files with 129 additions and 11 deletions
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30
src/vm_x86.dasc
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@@ -2045,7 +2045,12 @@ static void build_subroutines(BuildCtx *ctx)
|.else
|.ffunc_n math_sqrt; fsqrt; jmp ->fff_resn
|.endif
|.ffunc_n math_log, fldln2; fyl2x; jmp ->fff_resn
|
|.ffunc math_log
| cmp NARGS:RD, 1+1; jne ->fff_fallback // Exactly one argument.
| cmp dword [BASE+4], LJ_TISNUM; jae ->fff_fallback
| fldln2; fld qword [BASE]; fyl2x; jmp ->fff_resn
|
|.ffunc_n math_log10, fldlg2; fyl2x; jmp ->fff_resn
|.ffunc_n math_exp; call ->vm_exp_x87; jmp ->fff_resn
|
@@ -3157,6 +3162,29 @@ static void build_subroutines(BuildCtx *ctx)
| ret
|.endif
|
|// FP log2(x). Called by math.log(x, base).
|->vm_log2:
|.if X64WIN
| movsd qword [rsp+8], xmm0 // Use scratch area.
| fld1
| fld qword [rsp+8]
| fyl2x
| fstp qword [rsp+8]
| movsd xmm0, qword [rsp+8]
|.elif X64
| movsd qword [rsp-8], xmm0 // Use red zone.
| fld1
| fld qword [rsp-8]
| fyl2x
| fstp qword [rsp-8]
| movsd xmm0, qword [rsp-8]
|.else
| fld1
| fld qword [esp+4]
| fyl2x
|.endif
| ret
|
|// FP exponentiation e^x and 2^x. Called by math.exp fast function and
|// from JIT code. Arg/ret on x87 stack. No int/xmm regs modified.
|// Caveat: needs 3 slots on x87 stack!