cpu/pred/statistical_corrector.cc

149 StatisticalCorrector::getIndBias(Addr branch_pc, BranchInfo* bi,
152     return (((((branch_pc ^(branch_pc >>2))<<1) ^ (bi->lowConf & bias)) <<1)
153             +  bi->predBeforeSC) & ((1<<logBias) -1);
157 StatisticalCorrector::getIndBiasSK(Addr branch_pc, BranchInfo* bi) const
160            (bi->highConf))<<1) + bi->predBeforeSC) & ((1<<logBias) -1);
205                    BranchInfo* bi)
215     int xsum = bi->lsum - ((w[getIndUpds(branch_pc)] >= 0)) * percsum;
224                      BranchInfo* bi, bool prev_pred_taken, bool bias_bit,
231         bi->predBeforeSC = prev_pred_taken;
235             bi->lowConf = (abs(2 * conf_ctr + 1) == 1);
236             bi->medConf = (abs(2 * conf_ctr + 1) == 5);
237             bi->highConf = (abs(2 * conf_ctr + 1) >= (1<<conf_bits) - 1);
242         int8_t ctr = bias[getIndBias(branch_pc, bi, bias_bit)];
244         ctr = biasSK[getIndBiasSK(branch_pc, bi)];
246         ctr = biasBank[getIndBiasBank(branch_pc, bi, hitBank, altBank)];
251         int thres = gPredictions(tid, branch_pc, bi, lsum, phist);
254         bi->lsum = lsum;
255         bi->thres = thres;
262             if (bi->highConf) {
270             if (bi->medConf) {
276             bi->usedScPred = useScPred;
279                 bi->scPred = scPred;
318         bool taken, BranchInfo *bi, Addr corrTarget, bool b, int hitBank,
321     bool scPred = (bi->lsum >= 0);
323     if (bi->predBeforeSC != scPred) {
324         if (abs(bi->lsum) < bi->thres) {
325             if (bi->highConf) {
326                 if ((abs(bi->lsum) < bi->thres / 2)) {
327                     if ((abs(bi->lsum) >= bi->thres / 4)) {
328                         ctrUpdate(secondH, (bi->predBeforeSC == taken),
334         if (bi->medConf) {
335             if ((abs(bi->lsum) < bi->thres / 4)) {
336                 ctrUpdate(firstH, (bi->predBeforeSC == taken),
342     if ((scPred != taken) || ((abs(bi->lsum) < bi->thres))) {
348         unsigned indBias = getIndBias(branch_pc, bi, b);
349         unsigned indBiasSK = getIndBiasSK(branch_pc, bi);
350         unsigned indBiasBank = getIndBiasBank(branch_pc, bi, hitBank, altBank);
352         int xsum = bi->lsum -
371         gUpdates(tid, branch_pc, taken, bi, phist);
376 StatisticalCorrector::updateStats(bool taken, BranchInfo *bi)
378     if (taken == bi->scPred) {