Cheri-research/cheri-cap-lib
1
0
Fork 0
Code Issues 1 Pull Requests Actions Packages Projects Releases Wiki Activity

Fixup base/top/repBase/repTop implementation

Browse Source
This commit is contained in:
gameboo
2021-09-28 12:05:35 +01:00
parent 5bb91d9d99
commit 6e20d177dc
1 changed files with 18 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
CHERICC_Fat.bsv
View File

@@ -256,7 +256,8 @@ typedef MetaInfo TempFields;
// Interface functions
//------------------------------------------------------------------------------
function BoundsInfo#(CapAddrW) getBoundsInfoFat (CapFat cap, TempFields tf)
provisos ( NumAlias #(upperW, TSub #(TAdd #(CapAddrW, 1), MW))
provisos ( NumAlias #(fullW, TAdd #(CapAddrW, 1))
, NumAlias #(upperW, TSub #(fullW, MW))
, NumAlias #(lowerW, MW) );
// shared useful bindings and precomputed values
@@ -272,10 +273,10 @@ function BoundsInfo#(CapAddrW) getBoundsInfoFat (CapFat cap, TempFields tf)
// prepare typed "lower" MW zeroes for simpler concatenation
Bit #(lowerW) lowerZeroes = 0;
// prepare "upper" version for baseBits, topBits and repBoundBits
Bit #(upperW) baseBitsUpper = zeroExtend (baseBits) << exp;
Bit #(upperW) topBitsUpper = zeroExtend (topBits) << exp;
Bit #(upperW) repBoundBitsUpper = zeroExtend (repBoundBits) << exp;
// prepare "full" version for baseBits, topBits and repBoundBits
Bit #(fullW) baseBitsFull = zeroExtend (baseBits) << exp;
Bit #(fullW) topBitsFull = zeroExtend (topBits) << exp;
Bit #(fullW) repBoundBitsFull = zeroExtend (repBoundBits) << exp;
// shared +1 and -1/~0 shifted by exponent
Bit #(upperW) allOnesExpShifted = ~0 << exp;
@@ -294,18 +295,18 @@ function BoundsInfo#(CapAddrW) getBoundsInfoFat (CapFat cap, TempFields tf)
//////////////////////////////////////////////////////////////////////////////
// Use the appropriate upper bits of the address based on whether the base is
// in the "hi" or the "lo" region, or in the base bits in place and append the
// implied zeros in the lower bits
// in the "hi" or the "lo" region, append implied zeroes in the lower bits,
// and or in the base bits
CapAddr base =
{truncate (addrUpper (tf.baseHi) | baseBitsUpper), lowerZeroes};
truncate ({addrUpper (tf.baseHi), lowerZeroes} | baseBitsFull);
// compute top
//////////////////////////////////////////////////////////////////////////////
// Use the appropriate upper bits of the address based on whether the top is
// in the "hi" or the "lo" region, or in the top bits in place and append the
// implied zeros in the lower bits
CapAddrPlus1 top = {addrUpper (tf.topHi) | topBitsUpper, lowerZeroes};
// in the "hi" or the "lo" region, append implied zeroes in the lower bits,
// and or in the top bits
CapAddrPlus1 top = {addrUpper (tf.topHi), lowerZeroes} | topBitsFull;
// If the base and top are more than an address space away from eachother,
// invert the 64th/32nd bit of Top. This corrects for errors that happen when
// the representable space wraps the address space.
@@ -339,17 +340,17 @@ function BoundsInfo#(CapAddrW) getBoundsInfoFat (CapFat cap, TempFields tf)
// compute repBase
//////////////////////////////////////////////////////////////////////////////
// Use the "lo" region upper bits of the address, or in the representable
// bound bits in place and append the implied zeros in the lower bits
// Use the "lo" region upper bits of the address, append implied zeroes in the
// lower bits, and or in the representable bound bits
CapAddr repBase =
{truncate (addrUpperLo | repBoundBitsUpper), lowerZeroes};
truncate ({addrUpperLo, lowerZeroes} | repBoundBitsFull);
// compute repTop
//////////////////////////////////////////////////////////////////////////////
// Use the "hi" region upper bits of the address, or in the representable
// bound bits in place and append the implied zeros in the lower bits
CapAddrPlus1 repTop = {addrUpperHi | repBoundBitsUpper, lowerZeroes};
// Use the "hi" region upper bits of the address, append implied zeroes in the
// lower bits, and or in the representable bound bits
CapAddrPlus1 repTop = {addrUpperHi, lowerZeroes} | repBoundBitsFull;
// compute repLength
//////////////////////////////////////////////////////////////////////////////