DIRECTORYCommander,FS,IO,Real,RealFns,Rope,U255;LarkSineTableImpl: PROGRAM IMPORTS Commander, FS, IO, Real, RealFns, U255 = {OPEN U255;Main: Commander.CommandProc = TRUSTED {ENABLE ABORTED => GOTO Quit;out: IO.STREAM;name: Rope.ROPE;label: Rope.ROPE;res: BOOL;l: NAT;loss: REAL;out _ cmd.out;out.PutF["\nLarkSineTables running at %t\n", IO.time[]];FOR i: NAT IN [0..7] DOl _ i*3;loss _ l;loss _ loss - 3.16; -- codec clipping level is at 3.16 dBname _ IO.PutFR["SineTable%02d.dsm", IO.int[l]];label _ IO.PutFR["STab%02d", IO.int[l]];out.PutF["Writing %g ... ", IO.rope[name]];res _ WriteDSMFile[label: label, name: name, data: MakeSineTable[dBToLoss[l]]];out.PutF[IF res THEN "OK.\n" ELSE "Failed!\n"];ENDLOOP;out.PutF["\nLarkSineTables finished at %t\n", IO.time[]];out.Flush[];EXITSQuit => NULL;};Pi: REAL = 3.1415926535;TwoPi: REAL = 2.0 * Pi;MakeSineTable: PROC [loss: REAL] RETURNS [t: REF BTab] = {int: INTEGER;x: REAL;t _ NEW[BTab[256]];FOR i: CARDINAL IN [0..256) DOx _ i;x _ x/256.0;   -- fraction of circlex _ x * TwoPi;  -- phase in radiansx _ RealFns.Sin[x];  -- IN [-1..1]x _ x*loss;  -- attenuatex _ x*32767;  -- scale to left justified two's complementint _ Real.FixI[x];  -- Fixt[i] _ U255.Encode[int];ENDLOOP;};WriteDSMFile: PROC [label: Rope.ROPE, name: Rope.ROPE, data: REF BTab] RETURNS [BOOL] = {f: IO.STREAM;IF data.length MOD 2 # 0 THEN GOTO Fail;f _ FS.StreamOpen[fileName: name, accessOptions: $create ! FS.Error => TRUSTED {GOTO Fail}];f.PutF["; %g\n; L. Stewart %t\n\n", IO.rope[name], IO.time[]];f.PutF["\nC_CODE   SEGMENT\n\n"];f.PutF["_%g\tLABEL\tNEAR\n", IO.rope[label]];FOR i: CARDINAL IN [0..data.length/2) DOf.PutF["\tDW\t0%02x%02xH\n", IO.card[data[i+i+1]], IO.card[data[i+i]]];ENDLOOP;f.PutF["\n\nPUBLIC  _%g\n\nC_CODE ENDS\n\tEND\n", IO.rope[label]];f.Close[];RETURN [TRUE];EXITSFail => RETURN [FALSE];};dBToLoss: PROC [dBloss: REAL] RETURNS [loss:REAL] = {RETURN [RealFns.Power[base: 10.0, exponent: -dBloss/20.0]];};Init: PROC = { Commander.Register["LarkSineTables", Main, "Make Lark Sinewave tables"]; };Init[];}.  Â  LarkSineTableImpl.mesaLast modified:Stewart,  December 22, 1983 3:11 pmConstructs a 256 x 8 bit tableAddress = phase fraction [0..255]Value = u-255 value = sine(phase) attenuated by lossMain programStewart,  October 27, 1982 11:05 pmStewart,  March 18, 1983 8:26 pm, Cedar 3.5Stewart,  June 6, 1983 12:36 pm, more sine tablesStewart,  September 29, 1983 9:52 pm, added 3.16 dB correction!Stewart,  December 22, 1983 3:11 pm, Cedar 5Ê§  ˜ Jšœ™Jšœ™Jšœ#™#J˜ šÏk	˜	J˜
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