divw
Signed 32-bit division
This instruction is defined by:
Synopsis
Divide the lower 32-bits of register xs1 by the lower 32-bits of register xs2, and store the sign-extended 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(), $encoding);
}
Bits<32> src1 = X[xs1][31:0];
Bits<32> src2 = X[xs2][31:0];
if (src2 == 0) {
X[xd] = {MXLEN{1'b1}};
} else if ((src1 == 32'h80000000) && (src2 == 32'hFFFFFFFF)) {
X[xd] = 0xffffffff80000000;
} else {
X[xd] = sext($signed(src1) / $signed(src2), 32);
}if (implemented?(ExtensionName::M) && (misa.M == 1'b0)) {
raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
Bits<32> src1 = X[xs1][31:0];
Bits<32> src2 = X[xs2][31:0];
if (src2 == 0) {
X[xd] = {MXLEN{1'b1}};
} else if ((src1 == 32'h80000000) && (src2 == 32'hFFFFFFFF)) {
X[xd] = sext(32'h80000000, 32);
} else {
X[xd] = sext($signed(src1) / $signed(src2), 32);
}