SinCos lookup
Posted: Thu Jul 11, 2013 7:55 am
Sometimes you need both the Sin and Cos value of an angle.
Here's a fast lookup procedure that returns an approximation of both (SSE required).
Input angle should be between -4095 PI and 4095 PI
Usage:
Here's a fast lookup procedure that returns an approximation of both (SSE required).
Input angle should be between -4095 PI and 4095 PI
Code: Select all
; *** Prepare SinCosTable (4 MiB) ***
Global Dim SinCosTable.f(1048575)
Procedure SinCosTableInit()
Protected i.i, s.f, m.f = #PI / 524288
For i = 0 To 524287
s = Sin(i * m)
SinCosTable(i) = s
SinCosTable(i + 524288) = -s
Next
EndProcedure
SinCosTableInit()
; *** SinCos Procedure (SSE required) ***
Procedure SinCos(Angle.f, *Sin.Float, *Cos.Float)
!mov eax, 0x4822f983
!movd xmm0, eax
!mulss xmm0, [p.v_Angle]
!cvtss2si eax, xmm0
!lea ecx, [eax + 262144]
!and eax, 0xfffff
!and ecx, 0xfffff
CompilerIf #PB_Compiler_Processor = #PB_Processor_x64
!mov rdx, [a_SinCosTable]
!mov eax, [rdx + rax * 4]
!mov ecx, [rdx + rcx * 4]
!mov rdx, [p.p_Sin]
!mov [rdx], eax
!mov rdx, [p.p_Cos]
!mov [rdx], ecx
CompilerElse
!mov edx, [a_SinCosTable]
!mov eax, [edx + eax * 4]
!mov ecx, [edx + ecx * 4]
!mov edx, [p.p_Sin]
!mov [edx], eax
!mov edx, [p.p_Cos]
!mov [edx], ecx
CompilerEndIf
EndProcedureCode: Select all
Define S.f, C.f
SinCos(0.234, @S, @C)
Debug S
Debug C