[Lightning] Re: Still problems.

[Paolo Bonzini]

> 3) modified jit_shift_args to use nbargs instead.
>
> #define jit_shift_args() \
>    ((_jitl.nbargs >= 3 ? (void) (MOVQrr(_R10D, _RDX)) : (void) 0), \
>     (_jitl.nbargs >= 4 ? (void) (MOVQrr(_R11D, _RCX)) : (void) 0))
>
> With this change, it moves the values as expected.

It turns out that with JIT_Rx mapped to RAX/R10/R11 there is no need for 
jit_shift_args anymore.  That's good!

I attach the patch I committed so that you can see what's going on.

Paolo

diff --git a/ChangeLog b/ChangeLog
index 1e05fe1..0d0f86a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2008-06-16  Paolo Bonzini  <address@hidden>
+
+       * lightning/i386/core.h: Use jit_save in jit_replace.  Move JIT_R
+       definition...
+       * lightning/i386/core-32.h: ... here; define jit_save so that
+       the core.h has no effect on the 32-bit backend.
+       * lightning/i386/core-64.h: Place JIT_R1/JIT_R2 in R10/R11,
+       place outgoing arguments in the right spot from the beginning,
+       define jit_save, fix jit_reg8/jit_reg16.
+
 2008-06-15  Paolo Bonzini  <address@hidden>
 
         * lightning/i386/core-64.h: Rewrite argument passing to
diff --git a/lightning/i386/core-32.h b/lightning/i386/core-32.h
index 9775fc8..46b3516 100644
--- a/lightning/i386/core-32.h
+++ b/lightning/i386/core-32.h
@@ -36,6 +36,9 @@
 
 #define JIT_CAN_16 1
 #define JIT_AP                 _EBP
+
+#define JIT_R_NUM              3
+#define JIT_R(i)               (_EAX + (i))
 #define JIT_V_NUM              3
 #define JIT_V(i)               ((i) == 0 ? _EBX : _ESI + (i) - 1)
 
@@ -46,6 +49,9 @@ struct jit_local_state {
   int  alloca_slack;
 };
 
+/* Whether a register is used for the user-accessible registers.  */
+#define jit_save(reg)          1
+
 #define jit_base_prolog() (_jitl.framesize = 20, _jitl.alloca_offset = 0, \
   PUSHLr(_EBX), PUSHLr(_ESI), PUSHLr(_EDI), PUSHLr(_EBP), MOVLrr(_ESP, _EBP))
 #define jit_base_ret(ofs)                                                \
diff --git a/lightning/i386/core-64.h b/lightning/i386/core-64.h
index 173a229..5da7535 100644
--- a/lightning/i386/core-64.h
+++ b/lightning/i386/core-64.h
@@ -38,6 +38,8 @@
 #define JIT_CAN_16 0
 #define JIT_REXTMP             _R9D
 
+#define JIT_R_NUM              3
+#define JIT_R(i)                ((i) == 0 ? _EAX : _R9D + (i))
 #define JIT_V_NUM               3
 #define JIT_V(i)                ((i) == 0 ? _EBX : _R11D + (i))
 
@@ -51,6 +53,9 @@ struct jit_local_state {
   int   alloca_slack;
 };
 
+/* Whether a register in the "low" bank is used for the user-accessible
+   registers.  */
+#define jit_save(reg)          ((reg) == _EAX || (reg) == _EBX)
 
 /* Keep the stack 16-byte aligned, the SSE hardware prefers it this way.  */
 #define jit_allocai_internal(amount, slack)                           \
@@ -128,19 +133,13 @@ struct jit_local_state {
 /* Stack isn't used for arguments: */
 #define jit_prepare_i(ni)      (_jitl.argssize = (ni))
 
-#define jit_pusharg_i(rs)      (--_jitl.argssize, MOVQrr(rs, 
jit_arg_reg_temp[_jitl.argssize]))
-#define jit_finish(sub)         (jit_shift_args(), \
-                                MOVQir((long) (sub), JIT_REXTMP), \
+#define jit_pusharg_i(rs)      (--_jitl.argssize, MOVQrr(rs, 
jit_arg_reg_order[_jitl.argssize]))
+#define jit_finish(sub)         (MOVQir((long) (sub), JIT_REXTMP), \
                                 CALLsr(JIT_REXTMP))
 #define jit_reg_is_arg(reg)     ((reg) == _ECX || (reg) == _EDX)
 #define jit_finishr(reg)       ((jit_reg_is_arg((reg)) ? MOVQrr(reg, 
JIT_REXTMP) : (void)0), \
-                                 jit_shift_args(), \
                                  CALLsr(jit_reg_is_arg((reg)) ? JIT_REXTMP : 
(reg)))
 
-#define jit_shift_args() \
-   ((_jitl.argssize >= 3 ? (void) (MOVQrr(_R10D, _RDX)) : (void) 0), \
-    (_jitl.argssize >= 4 ? (void) (MOVQrr(_R11D, _RCX)) : (void) 0))
-
 #define jit_retval_l(rd)       ((void)jit_movr_l ((rd), _EAX))
 #define        jit_arg_c()             
(jit_arg_reg_order[_jitl.nextarg_geti++])
 #define        jit_arg_uc()            
(jit_arg_reg_order[_jitl.nextarg_geti++])
@@ -152,7 +151,6 @@ struct jit_local_state {
 #define        jit_arg_ul()            
(jit_arg_reg_order[_jitl.nextarg_geti++])
 #define        jit_arg_p()             
(jit_arg_reg_order[_jitl.nextarg_geti++])
 
-static int jit_arg_reg_temp[] = { _EDI, _ESI, _R10D, _R11D, _R8D, _R9D };
 static int jit_arg_reg_order[] = { _EDI, _ESI, _EDX, _ECX, _R8D, _R9D };
 
 #define jit_negr_l(d, rs)      jit_opi_((d), (rs), NEGQr(d), (XORQrr((d), 
(d)), SUBQrr((rs), (d))) )
@@ -185,8 +183,8 @@ static int jit_arg_reg_order[] = { _EDI, _ESI, _EDX, _ECX, 
_R8D, _R9D };
 
 /* Used to implement ldc, stc, ... We have SIL and friends which simplify it 
all.  */
 #define jit_check8(rs)          1
-#define jit_reg8(rs)            (_rN(rs) | _AL )
-#define jit_reg16(rs)           (_rN(rs) | _AX )
+#define jit_reg8(rs)            (_rR(rs) | _AL )
+#define jit_reg16(rs)           (_rR(rs) | _AX )
 #define jit_movbrm(rs, dd, db, di, ds)         MOVBrm(jit_reg8(rs), dd, db, 
di, ds)
 
 #define jit_ldi_c(d, is)                (_u32P((long)(is)) ? MOVSBLmr((is), 0, 
   0,    0, (d)) :  (jit_movi_l(JIT_REXTMP, is), jit_ldr_c(d, JIT_REXTMP)))
diff --git a/lightning/i386/core.h b/lightning/i386/core.h
index ad99d4d..64f8e80 100644
--- a/lightning/i386/core.h
+++ b/lightning/i386/core.h
@@ -38,9 +38,6 @@
 #define JIT_SP                 _ESP
 #define JIT_RET                        _EAX
 
-#define JIT_R_NUM              3
-#define JIT_R(i)               (_EAX + (i))
-
 
 /* 3-parameter operation */
 #define jit_opr_(d, s1, s2, op1d, op2d)                                        
\
@@ -64,7 +61,11 @@
 /* An operand is forced into a register */
 #define jit_replace(rd, rs, forced, op)                                        
\
        ((rd == forced) ? JITSORRY("Register conflict for " # op) :     \
-        (rs == forced) ? op : (jit_pushr_i(forced), MOVLrr(rs, forced), op, 
jit_popr_i(forced)))
+        (rs == forced) ? op :                                          \
+        jit_save (forced)                                              \
+         ? (jit_pushr_i(forced), jit_movr_l(rs, forced), op,           \
+            jit_popr_i(forced))                                        \
+         : (jit_movr_l(rs, forced), op))
 
 /* For LT, LE, ... */
 #define jit_replace8(d, cmp, op)                               \