X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FnativeGen%2FX86%2FInstr.hs;h=26da90778c82dca0c37c0e2a5dde6aa14496d752;hb=72636a93a047af23461df5123edc2342b2dec48d;hp=b4b6fb5f4be684a9a93f2b360a52e65dca8028a1;hpb=b04a210e26ca57242fd052f2aa91011a80b76299;p=ghc-hetmet.git

diff --git a/compiler/nativeGen/X86/Instr.hs b/compiler/nativeGen/X86/Instr.hs
index b4b6fb5..26da907 100644
--- a/compiler/nativeGen/X86/Instr.hs
+++ b/compiler/nativeGen/X86/Instr.hs
@@ -23,6 +23,8 @@ import BlockId
 import Cmm
 import FastString
 import FastBool
+import Outputable
+import Constants	(rESERVED_C_STACK_BYTES)
 
 import CLabel
 import Panic
@@ -655,6 +657,23 @@ x86_mkLoadInstr _ _ _
  	= panic "X86.RegInfo.mkLoadInstr: not defined for this architecture."
 #endif
 
+spillSlotSize :: Int
+spillSlotSize = IF_ARCH_i386(12, 8)
+
+maxSpillSlots :: Int
+maxSpillSlots = ((rESERVED_C_STACK_BYTES - 64) `div` spillSlotSize) - 1
+
+-- convert a spill slot number to a *byte* offset, with no sign:
+-- decide on a per arch basis whether you are spilling above or below
+-- the C stack pointer.
+spillSlotToOffset :: Int -> Int
+spillSlotToOffset slot
+   | slot >= 0 && slot < maxSpillSlots
+   = 64 + spillSlotSize * slot
+   | otherwise
+   = pprPanic "spillSlotToOffset:" 
+              (   text "invalid spill location: " <> int slot
+	      $$  text "maxSpillSlots:          " <> int maxSpillSlots)
 
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