div
Signed division
This instruction is defined by:
Synopsis
Divide xs1 by xs2, and store the result in xd. The remainder is discarded.
Division by zero will put -1 into xd.
Division resulting in signed overflow (when most negative number is divided by -1) will put the most negative number into xd;
Decode Variables
Bits<5> xs2 = $encoding[24:20];
Bits<5> xs1 = $encoding[19:15];
Bits<5> xd = $encoding[11:7];Execution
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Pruned, XLEN == 64
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Original
if (implemented?(ExtensionName::M) && (misa.M == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg src1 = X[xs1];
XReg src2 = X[xs2];
XReg signed_min = {1'b1, {63{1'b0}}};
if (src2 == 0) {
X[xd] = {MXLEN{1'b1}};
} else if ((src1 == signed_min) && (src2 == {MXLEN{1'b1}})) {
X[xd] = signed_min;
} else {
X[xd] = $signed(src1) / $signed(src2);
}if (implemented?(ExtensionName::M) && (misa.M == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg src1 = X[xs1];
XReg src2 = X[xs2];
XReg signed_min = (xlen() == 32) ? $signed({1'b1, {31{1'b0}}}) : {1'b1, {63{1'b0}}};
if (src2 == 0) {
X[xd] = {MXLEN{1'b1}};
} else if ((src1 == signed_min) && (src2 == {MXLEN{1'b1}})) {
X[xd] = signed_min;
} else {
X[xd] = $signed(src1) / $signed(src2);
}