Re: [Lightning] Shift instructions

[Mike Spivey]

I spoke five minutes too soon:

diff --git a/lightning/i386/core.h b/lightning/i386/core.h
index 86aee39..2f017f9 100644
--- a/lightning/i386/core.h
+++ b/lightning/i386/core.h
@@ -63,7 +63,7 @@
        ((rd == forced) ? JITSORRY("Register conflict for " # op) :     \
         (rs == forced) ? op :                                          \
         jit_save (forced)                                              \
-         ? (jit_pushr_i(forced), jit_movr_l(rs, forced), op,           \
+         ? (jit_pushr_i(forced), jit_movr_l(forced, rs), op,           \
             jit_popr_i(forced))                                        \
          : (jit_movr_l(rs, forced), op))

Best wishes,

-- Mike

Mike Spivey wrote:
> Dear Paolo and all,
> 
> Attached is a program that attempts to compute (-16) << 2.  The result
> should be -64, but -16 is printed on i386.
> 
> I've tried a number of combinations, but haven't quite tracked down the
> problem yet:
> 
> * Use JIT_R1 instead of JIT_V0 throughout --> fixed.
> 
> * Insert jit_movi_i(JIT_R1, 3); before the shift instruction (but leave
> instruction referring to JIT_V0) --> result is -128.
> 
> * Use a jit_mulr_i instruction instead of the shift --> correct result.
> 
> * Use jit_lshi_i instead of jit_lshr_i --> correct result.
> 
> So it looks like the problem concerns putting the shift amount into the
> ECX register before the actual shift instruction.
> 
> I am sorry to be always the bearer of bad tidings, but there it is!  Can
> anything be done?
> 
> Best wishes,
> 
> -- Mike
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Lightning mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/lightning