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Fix constant shifts by more than 32-bit numbers, bug1174 continued.

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This commit is contained in:
Wilson Snyder 2017-06-05 21:15:31 -04:00
parent 97093fdf81
commit c54024a5e6
2 changed files with 19 additions and 1 deletions
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15
src/V3Number.cpp
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@ -1217,6 +1217,9 @@ V3Number& V3Number::opShiftR (const V3Number& lhs, const V3Number& rhs) {
// L(lhs) bit return // L(lhs) bit return
if (rhs.isFourState()) return setAllBitsX(); if (rhs.isFourState()) return setAllBitsX();
setZero(); setZero();
for (int bit=32; bit<rhs.width(); bit++) {
if (rhs.bitIs1(bit)) return *this; // shift of over 2^32 must be zero
}
uint32_t rhsval = rhs.toUInt(); uint32_t rhsval = rhs.toUInt();
if (rhsval < (uint32_t)lhs.width()) { if (rhsval < (uint32_t)lhs.width()) {
for (int bit=0; bit<this->width(); bit++) { for (int bit=0; bit<this->width(); bit++) {
@ -1232,6 +1235,13 @@ V3Number& V3Number::opShiftRS (const V3Number& lhs, const V3Number& rhs, uint32_
// We presume it is signed; as that's V3Width's job to convert to opShiftR // We presume it is signed; as that's V3Width's job to convert to opShiftR
if (rhs.isFourState()) return setAllBitsX(); if (rhs.isFourState()) return setAllBitsX();
setZero(); setZero();
for (int bit=32; bit<rhs.width(); bit++) {
for (int bit=0; bit<this->width(); bit++) {
setBit(bit,lhs.bitIs(lbits-1)); // 0/1/X/Z
}
if (rhs.bitIs1(lbits-1)) setAllBits1(); // -1 else 0
return *this; // shift of over 2^32 must be -1/0
}
uint32_t rhsval = rhs.toUInt(); uint32_t rhsval = rhs.toUInt();
if (rhsval < (uint32_t)lhs.width()) { if (rhsval < (uint32_t)lhs.width()) {
for (int bit=0; bit<this->width(); bit++) { for (int bit=0; bit<this->width(); bit++) {
@ -1239,7 +1249,7 @@ V3Number& V3Number::opShiftRS (const V3Number& lhs, const V3Number& rhs, uint32_
} }
} else { } else {
for (int bit=0; bit<this->width(); bit++) { for (int bit=0; bit<this->width(); bit++) {
setBit(bit,lhs.bitIs(lbits-1)); setBit(bit,lhs.bitIs(lbits-1)); // 0/1/X/Z
} }
} }
return *this; return *this;
@ -1249,6 +1259,9 @@ V3Number& V3Number::opShiftL (const V3Number& lhs, const V3Number& rhs) {
// L(lhs) bit return // L(lhs) bit return
if (rhs.isFourState()) return setAllBitsX(); if (rhs.isFourState()) return setAllBitsX();
setZero(); setZero();
for (int bit=32; bit<rhs.width(); bit++) {
if (rhs.bitIs1(bit)) return *this; // shift of over 2^32 must be zero
}
uint32_t rhsval = rhs.toUInt(); uint32_t rhsval = rhs.toUInt();
for (int bit=0; bit<this->width(); bit++) { for (int bit=0; bit<this->width(); bit++) {
if (bit >= (int)rhsval) { if (bit >= (int)rhsval) {

5
test_regress/t/t_math_shift.v
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@ -18,6 +18,11 @@ module t (/*AUTOARG*/
parameter [95:0] P6 = 6; parameter [95:0] P6 = 6;
localparam P64 = (1 << P6); localparam P64 = (1 << P6);
// verilator lint_off WIDTH
localparam [4:0] PBIG23 = 1'b1 << ~73'b0;
localparam [3:0] PBIG29 = 4'b1 << 33'h100000000;
// verilator lint_on WIDTH
reg [31:0] right; reg [31:0] right;
reg [31:0] left; reg [31:0] left;
reg [P64-1:0] qright; reg [P64-1:0] qright;