div
Signed division
This instruction is defined by:
Synopsis
Divide rs1 by rs2, and store the result in rd. The remainder is discarded.
Division by zero will put -1 into rd.
Division resulting in signed overflow (when most negative number is divided by -1) will put the most negative number into rd;
Decode Variables
Bits<5> rs2 = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];Execution
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Pruned, XLEN == 64
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Original
if ((%%LINK%csr_field;misa.M;CSR[misa].M%% == 1'b0)) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
XReg src1 = X[rs1];
XReg src2 = X[rs2];
XReg signed_min = {1'b1, {63{1'b0}}};
if (src2 == 0) {
X[rd] = {MXLEN{1'b1}};
} else if ((src1 == signed_min) && (src2 == {MXLEN{1'b1}})) {
X[rd] = signed_min;
} else {
X[rd] = $signed(src1) / $signed(src2);
}if (%%LINK%func;implemented?;implemented?%%(ExtensionName::M) && (%%LINK%csr_field;misa.M;CSR[misa].M%% == 1'b0)) {
%%LINK%func;raise;raise%%(ExceptionCode::IllegalInstruction, %%LINK%func;mode;mode%%(), $encoding);
}
XReg src1 = X[rs1];
XReg src2 = X[rs2];
XReg signed_min = (%%LINK%func;xlen;xlen%%() == 32) ? $signed({1'b1, {31{1'b0}}}) : {1'b1, {63{1'b0}}};
if (src2 == 0) {
X[rd] = {MXLEN{1'b1}};
} else if ((src1 == signed_min) && (src2 == {MXLEN{1'b1}})) {
X[rd] = signed_min;
} else {
X[rd] = $signed(src1) / $signed(src2);
}