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FFT_twiddle in Funktion ausgelagert und in FFT_calc eingebracht

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unknown 2015-03-09 23:30:21 +01:00
parent 069ad23481
commit 818574c62e
2 changed files with 24 additions and 19 deletions
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17
fft.c
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@ -110,16 +110,13 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
/* it may not be obvious, but the shift will be performed
on each data point exactly once, during this pass. */
istep = l << 1; //step width of current butterfly
for(m=0; m<l; ++m)
FFT_reg reg;
fixed *reg_s = ((fixed*) &reg);
for(m=0; m<n; m+=istep)
{
j = m << k;
FFT_twiddle(wr, wi, j, shift, inverse);
FFT_reg reg;
fixed *reg_s = ((fixed*) &reg);
for(i=m; i<n; i+=istep)
for(i=m; i<m+l; ++i)
{
j = i + l;
@ -128,7 +125,7 @@ int fix_fft(fixed fr[], fixed fi[], int m, int inverse)
reg_s[1] = fi[i];
reg_s[0] = fi[j];
FFT_calc(reg, wr, wi, shift);
FFT_calc(reg, i << k, (xtbool) shift, inverse);
fr[i] = reg_s[3];
fr[j] = reg_s[2];

26
fft_inst.tie
View File

@ -181,7 +181,7 @@ operation FFT_bit_reverse {inout AR m, out AR mr, in AR mm} {}
assign m = x;
}
operation FFT_twiddle {out AR wr, out AR wi, in AR j, in BR shift, in BR inverse} {}
function [31:0] FFT_twiddle ([31:0] j, [0:0] shift, [0:0] inverse)
{
// 256 = N_WAVE / 4
wire [9:0] idx = TIEadd(j, 256, 1'b0);
@ -189,13 +189,11 @@ operation FFT_twiddle {out AR wr, out AR wi, in AR j, in BR shift, in BR inverse
wire [15:0] wr1 = SIN_wave[idx];
wire [15:0] wi1 = TIEadd(~sin, 16'b0, 1'b1);
wire [15:0] wi2 = TIEmux(inverse, wi1, sin);
assign wr = TIEmux(shift, wr1, {wr1[15], wr1[15:1]});
assign wi = TIEmux(shift, wi2, {wi2[15], wi2[15:1]});
}
operation FFT_calc {inout FFT_reg data, in AR wr, in AR wi, in AR shift} {}
{
assign data = FFT_butterfly(data, wr, wi, shift);
assign FFT_twiddle = {
TIEmux(shift, wr1, {wr1[15], wr1[15:1]}),
TIEmux(shift, wi2, {wi2[15], wi2[15:1]})
};
}
function [63:0] FFT_butterfly ([63:0] data, [15:0] wr, [15:0] wi, [0:0] shift) {
@ -235,6 +233,16 @@ function [63:0] FFT_butterfly ([63:0] data, [15:0] wr, [15:0] wi, [0:0] shift) {
assign FFT_butterfly = { resr1, resr2, resi1, resi2 };
}
operation FFT_calc {inout FFT_reg data, in AR i, in BR shift, in BR inverse} {}
{
wire [31:0] twiddle = FFT_twiddle(i, shift, inverse);
wire [15:0] wr = twiddle[31:16];
wire [15:0] wi = twiddle[15:0];
assign data = FFT_butterfly(data, wr, wi, shift);
}
////////////////////////////////////////////////////////////////////////////
//
// Generated by XPRES v4.0.4
@ -310,7 +318,7 @@ immediate_range ld.FFT_reg_immed2 -32 24 8
format flix64_0 64 { flix64_0_slot0, flix64_0_slot1, flix64_0_slot2 }
slot_opcodes Inst {
FFT_bit_reverse, FFT_calc, FFT_twiddle, ld.FFT_reg,
FFT_bit_reverse, FFT_calc, ld.FFT_reg,
mv.FFT_reg, st.FFT_reg }
slot_opcodes flix64_0_slot0 {
ADD, BEQZ, BGEU, BLTU, BNEZ, L16SI, MOV.N, NOP, S16I, SEXT, SUB, FFT_shift_check }