[project @ 2001-08-22 14:32:19 by sewardj]

On sparc, create code to shuffle %i0 .. %i3 into %i2 .. %i5 before the
old code.  This is a GHASTLY HACK which at least makes f-x-dynamic on
sparc work for callees with up to 16 bytes (4 words) of args.

diff --git a/ghc/rts/Adjustor.c b/ghc/rts/Adjustor.c
index 4d6c223..8f12e84 100644 (file)
--- a/ghc/rts/Adjustor.c
+++ b/ghc/rts/Adjustor.c
@@ -155,12 +155,16 @@ createAdjustor(int cconv, StgStablePtr hptr, StgFunPtr wptr)
      the following assembly language snippet
      (offset and machine code prefixed):
 
      the following assembly language snippet
      (offset and machine code prefixed):
 

-  <00>: 13 00 3f fb     sethi  %hi(0x00ffeffa), %o1 # load up wptr (1 of 2)
-  <04>: 11 37 ab 6f     sethi  %hi(0xdeadbeef), %o0 # load up hptr (1 of 2)
-  <08>: 81 c2 63 fa     jmp    %o1+%lo(0x00ffeffa)  # jump to wptr (load 2 of 2)
-  <0c>: 90 12 22 ef     or     %o0, %lo(0xdeadbeef), %o0 # load up hptr (2 of 2)
+  <00>: BA 10 00 1B     mov    %i3, %i5
+  <04>: B8 10 00 1A     mov    %i2, %i4
+  <08>: B6 10 00 19     mov    %i1, %i3
+  <0c>: B4 10 00 18     mov    %i0, %i2
+  <10>: 13 00 3f fb     sethi  %hi(0x00ffeffa), %o1 # load up wptr (1 of 2)
+  <14>: 11 37 ab 6f     sethi  %hi(0xdeadbeef), %o0 # load up hptr (1 of 2)
+  <18>: 81 c2 63 fa     jmp    %o1+%lo(0x00ffeffa)  # jump to wptr (load 2 of 2)
+  <1c>: 90 12 22 ef     or     %o0, %lo(0xdeadbeef), %o0 # load up hptr (2 of 2)

                                                          # [in delay slot]
                                                          # [in delay slot]

-  <10>: de ad be ef     # Place the value of the StgStablePtr somewhere readable
+  <20>: de ad be ef     # Place the value of the StgStablePtr somewhere readable

 
     ccall'ing on a SPARC leaves little to be performed by the caller.
     The callee shifts the window on entry and restores it on exit.
 
     ccall'ing on a SPARC leaves little to be performed by the caller.
     The callee shifts the window on entry and restores it on exit.

@@ -168,27 +172,51 @@ createAdjustor(int cconv, StgStablePtr hptr, StgFunPtr wptr)
     code above contains the input paramter to wptr.) The return address
     is stored in %o7/%i7. Since we don't shift the window in this code,
     the return address is preserved and wptr will return to our caller.
     code above contains the input paramter to wptr.) The return address
     is stored in %o7/%i7. Since we don't shift the window in this code,
     the return address is preserved and wptr will return to our caller.

+
+    JRS, 21 Aug 01: the above para is a fiction.  The caller passes
+    args in %i0 .. %i5 and then the rest at [%sp+92].  We want to
+    tailjump to wptr, passing hptr as the new first arg, and a dummy
+    second arg, which would be where the return address is on x86.
+    That means we have to shuffle the original caller's args along by
+    two.
+
+    We do a half-correct solution which works only if the original
+    caller passed 4 or fewer arg words.  Move %i0 .. %i3 into %i3
+    .. %i6, so we can park hptr in %i0 and a bogus arg in %i1.  The
+    fully correct solution would be to subtract 8 from %sp and then
+    place %i4 and %i5 at [%sp+92] and [%sp+96] respectively.  This
+    machinery should then work in all cases.  (Or would it?  Perhaps
+    it would trash parts of the caller's frame.  Dunno).  

   */
   */

-    if ((adjustor = stgMallocBytes(28, "createAdjustor")) != NULL) {
-       unsigned char *const adj_code = (unsigned char *)adjustor;
+    if ((adjustor = stgMallocBytes(4*(8+1), "createAdjustor")) != NULL) {
+       unsigned long *const adj_code = (unsigned long *)adjustor;
+
+       /* mov  %o3, %o5 */
+       adj_code[0] = (unsigned long)0x9A10000B;
+       /* mov  %o2, %o4 */
+       adj_code[1] = (unsigned long)0x9810000A;
+       /* mov  %o1, %o3 */
+       adj_code[2] = (unsigned long)0x96100009;
+       /* mov  %o0, %o2 */
+       adj_code[3] = (unsigned long)0x94100008;

 
        /* sethi %hi(wptr), %o1 */
 
        /* sethi %hi(wptr), %o1 */

-       *((unsigned long*)(adj_code+0x00)) = (unsigned long)0x13000000;
-       *((unsigned long*)(adj_code+0x00)) |= ((unsigned long)wptr) >> 10;
+       adj_code[4] = (unsigned long)0x13000000;
+       adj_code[4] |= ((unsigned long)wptr) >> 10;

 
        /* sethi %hi(hptr), %o0 */
 
        /* sethi %hi(hptr), %o0 */

-       *((unsigned long*)(adj_code+0x04)) = (unsigned long)0x11000000;
-       *((unsigned long*)(adj_code+0x04)) |= ((unsigned long)hptr) >> 10;
+       adj_code[5] = (unsigned long)0x11000000;
+       adj_code[5] |= ((unsigned long)hptr) >> 10;

 
        /* jmp %o1+%lo(wptr) */
 
        /* jmp %o1+%lo(wptr) */

-       *((unsigned long*)(adj_code+0x08)) = (unsigned long)0x81c26000;
-       *((unsigned long*)(adj_code+0x08)) |= ((unsigned long)wptr) & 0x000003ff;
+       adj_code[6] = (unsigned long)0x81c26000;
+       adj_code[6] |= ((unsigned long)wptr) & 0x000003ff;

 
        /* or %o0, %lo(hptr), %o0 */
 
        /* or %o0, %lo(hptr), %o0 */

-       *((unsigned long*)(adj_code+0x0c)) = (unsigned long)0x90122000;
-       *((unsigned long*)(adj_code+0x0c)) |= ((unsigned long)hptr) & 0x000003ff;
+       adj_code[7] = (unsigned long)0x90122000;
+       adj_code[7] |= ((unsigned long)hptr) & 0x000003ff;

 
 

-       *((StgStablePtr*)(adj_code+0x10)) = (StgStablePtr)hptr;
+       adj_code[8] = (StgStablePtr)hptr;

     }
 #elif defined(alpha_TARGET_ARCH)
   /* Magic constant computed by inspecting the code length of
     }
 #elif defined(alpha_TARGET_ARCH)
   /* Magic constant computed by inspecting the code length of