| Quellcodebibliothek Statistik Leitseite products/sources/formale Sprachen/PVS/float/ (Beweissystem der NASA Version 6.0.9©) Datei vom 28.9.2014 mit Größe 1 kB |
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Quelle NaN_ops.pvs Sprache: PVS |
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NaN_ops
[b,p:above(1), E_max:integer, E_min:{i:integer|E_max>i}]: THEORY BEGIN IMPORTING IEEE_854_values[b,p,E_max,E_min], enumerated_type_defs %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Placeholders for defining results of operations on NaNs fp,fp1,fp2: var fp_num nan,nan1,nan2: var (NaN?) op: var fp_ops signal?(fp):bool = if NaN?(fp) then signal?(status(fp)) else false endif % mk_quiet takes an fp_num and coerces all NaNs into quiet NaNs. % all numeric floating-point arguments are left unchanged mk_quiet(fp): fp_num = if NaN?(fp) then NaN(quiet,data(fp)) else fp endif mk_quiet_correct: lemma not signal?(fp) => mk_quiet(fp) = fp fp_quiet(op,fp1,(fp2| NaN?(fp1) OR NaN?(fp2))):{nan| nan=fp1 or nan=fp2} fp_signal(op, fp1,(fp2| NaN?(fp1) OR NaN?(fp2))): fp_num = IF trap_enabled?(invalid_operation) THEN invalid ELSE fp_quiet(op, mk_quiet(fp1), mk_quiet(fp2)) ENDIF fp_nan(op, fp1, (fp2| NaN?(fp1) OR NaN?(fp2))): fp_num = IF signal?(fp1) OR signal?(fp2) THEN fp_signal(op, fp1, fp2) ELSE fp_quiet(op, fp1, fp2) ENDIF NaN_ops_correct: LEMMA NOT trap_enabled?(invalid_operation) & (NaN?(fp1) OR NaN?(fp2)) => quiet?(status(fp_nan(op, fp1, fp2))) fp_nan_x(op, fp1, (fp2| NaN?(fp1) OR NaN?(fp2))): [fp_num,exception] = IF signal?(fp1) OR signal?(fp2) THEN (fp_signal(op, fp1, fp2),invalid_operation) ELSE (fp_quiet(op, fp1, fp2), no_exceptions) ENDIF %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% NaN_sqrt(nan): fp_num = if signal?(status(nan)) & trap_enabled?(invalid_operation) then invalid else NaN(quiet,data(nan)) endif END NaN_ops ¤ Dauer der Verarbeitung: 0.15 Sekunden (vorverarbeitet) ¤*© Formatika GbR, Deutschland |
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2026-03-28