diff options
Diffstat (limited to 'includes/CodeGen.Platform.hs')
| -rw-r--r-- | includes/CodeGen.Platform.hs | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/includes/CodeGen.Platform.hs b/includes/CodeGen.Platform.hs index b93f0074fd..b41ad54349 100644 --- a/includes/CodeGen.Platform.hs +++ b/includes/CodeGen.Platform.hs @@ -874,17 +874,25 @@ freeRegBase _ = True #elif MACHREGS_powerpc -freeReg 0 = False -- Hack: r0 can't be used in all insns, - -- but it's actually free +freeReg 0 = False -- Used by code setting the back chain pointer + -- in stack reallocations on Linux + -- r0 is not usable in all insns so also reserved + -- on Darwin. freeReg 1 = False -- The Stack Pointer # if !MACHREGS_darwin -- most non-darwin powerpc OSes use r2 as a TOC pointer or something like that freeReg 2 = False --- TODO: make this conditonal for ppc64 ELF -freeReg 13 = False -- reserved for system thread ID --- TODO: do not reserve r30 in ppc64 ELF +freeReg 13 = False -- reserved for system thread ID on 64 bit -- at least linux in -fPIC relies on r30 in PLT stubs freeReg 30 = False +{- TODO: reserve r13 on 64 bit systems only and r30 on 32 bit respectively. + For now we use r30 on 64 bit and r13 on 32 bit as a temporary register + in stack handling code. See compiler/nativeGen/PPC/Ppr.hs. + + Later we might want to reserve r13 and r30 only where it is required. + Then use r12 as temporary register, which is also what the C ABI does. +-} + # endif # ifdef REG_Base freeReg REG_Base = False |