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Fix power operator on wide constants, bug761.

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Wilson Snyder
2017-06-05 20:30:01 -04:00
parent 50c4f60c68
commit 97093fdf81
8 changed files with 172 additions and 8 deletions
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include/verilated.cpp
+42
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@@ -282,6 +282,48 @@ WDataOutP _vl_moddiv_w(int lbits, WDataOutP owp, WDataInP lwp, WDataInP rwp, boo
}
}
WDataOutP VL_POW_WWW(int obits, int, int rbits, WDataOutP owp, WDataInP lwp, WDataInP rwp) {
owp[0] = 1;
for (int i=1; i < VL_WORDS_I(obits); i++) owp[i] = 0;
// cppcheck-suppress variableScope
WData powstore[VL_MULS_MAX_WORDS]; // Fixed size, as MSVC++ doesn't allow [words] here
WData lastpowstore[VL_MULS_MAX_WORDS]; // Fixed size, as MSVC++ doesn't allow [words] here
WData lastoutstore[VL_MULS_MAX_WORDS]; // Fixed size, as MSVC++ doesn't allow [words] here
// cppcheck-suppress variableScope
VL_ASSIGN_W(obits, powstore, lwp);
for (int bit=0; bit<rbits; bit++) {
if (bit>0) { // power = power*power
VL_ASSIGN_W(obits, lastpowstore, powstore);
VL_MUL_W(VL_WORDS_I(obits), powstore, lastpowstore, lastpowstore);
}
if (VL_BITISSET_W(rwp,bit)) { // out *= power
VL_ASSIGN_W(obits, lastoutstore, owp);
VL_MUL_W(VL_WORDS_I(obits), owp, lastoutstore, powstore);
}
}
return owp;
}
WDataOutP VL_POWSS_WWW(int obits, int, int rbits, WDataOutP owp, WDataInP lwp, WDataInP rwp, bool lsign, bool rsign) {
if (rsign && VL_SIGN_W(rbits, rwp)) {
int words = VL_WORDS_I(obits);
VL_ZERO_W(obits, owp);
IData lor = 0; // 0=all zeros, ~0=all ones, else mix
for (int i=1; i < (words-1); ++i) {
lor |= lwp[i];
}
lor |= ( (lwp[words-1] == VL_MASK_I(rbits)) ? ~VL_UL(0) : 0);
if (lor==0 && lwp[0]==0) { return owp; } // "X" so return 0
else if (lor==0 && lwp[0]==1) { owp[0] = 1; return owp; } // 1
else if (lsign && lor == ~VL_UL(0) && lwp[0]==~VL_UL(0)) { // -1
if (rwp[0] & 1) { return VL_ALLONES_W(obits, owp); } // -1^odd=-1
else { owp[0] = 1; return owp; } // -1^even=1
}
return 0;
}
return VL_POW_WWW(obits, rbits, rbits, owp, lwp, rwp);
}
//===========================================================================
// Formatting