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Refactored VM registerlayout. The size and location of the registers in (#12775)

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the instructions are now all derived from a single definition, allowing
the register layout to be changed.
This commit is contained in:
Ico Doornekamp 2019-11-30 13:38:36 +01:00 • committed by Andreas Rumpf
commit 6aade97fe8
2 changed files with 54 additions and 29 deletions
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43
compiler/vmdef.nim
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@ -12,17 +12,42 @@
import ast, idents, options, modulegraphs, lineinfos
type TInstrType* = uint32
const
regOBits = 8 # Opcode
regABits = 8
regBBits = 8
regCBits = 8
regBxBits = 16
byteExcess* = 128 # we use excess-K for immediates
wordExcess* = 32768
MaxLoopIterations* = 10_000_000 # max iterations of all loops
# Calculate register shifts, masks and ranges
const
regOShift* = 0.TInstrType
regAShift* = (regOShift + regOBits)
regBShift* = (regAShift + regABits)
regCShift* = (regBShift + regBBits)
regBxShift* = (regAShift + regABits)
regOMask* = ((1.TInstrType shl regOBits) - 1)
regAMask* = ((1.TInstrType shl regABits) - 1)
regBMask* = ((1.TInstrType shl regBBits) - 1)
regCMask* = ((1.TInstrType shl regCBits) - 1)
regBxMask* = ((1.TInstrType shl regBxBits) - 1)
wordExcess* = 1 shl (regBxBits-1)
regBxMin* = -wordExcess+1
regBxMax* = wordExcess-1
type
TRegister* = range[0..255]
TDest* = range[-1..255]
TInstr* = distinct uint32
TRegister* = range[0..regAMask.int]
TDest* = range[-1..regAMask.int]
TInstr* = distinct TInstrType
TOpcode* = enum
opcEof, # end of code
@ -254,10 +279,10 @@ const
# flag is used to signal opcSeqLen if node is NimNode.
const nimNodeFlag* = 16
template opcode*(x: TInstr): TOpcode = TOpcode(x.uint32 and 0xff'u32)
template regA*(x: TInstr): TRegister = TRegister(x.uint32 shr 8'u32 and 0xff'u32)
template regB*(x: TInstr): TRegister = TRegister(x.uint32 shr 16'u32 and 0xff'u32)
template regC*(x: TInstr): TRegister = TRegister(x.uint32 shr 24'u32)
template regBx*(x: TInstr): int = (x.uint32 shr 16'u32).int
template opcode*(x: TInstr): TOpcode = TOpcode(x.TInstrType shr regOShift and regOMask)
template regA*(x: TInstr): TRegister = TRegister(x.TInstrType shr regAShift and regAMask)
template regB*(x: TInstr): TRegister = TRegister(x.TInstrType shr regBShift and regBMask)
template regC*(x: TInstr): TRegister = TRegister(x.TInstrType shr regCShift and regCMask)
template regBx*(x: TInstr): int = (x.TInstrType shr regBxShift and regBxMask).int
template jmpDiff*(x: TInstr): int = regBx(x) - wordExcess