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Commit 5926dc51 authored by simonmar's avatar simonmar
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[project @ 2002-07-19 11:47:30 by simonmar] 

Code to make the general case of createAdjustor() work on Sparc, from
Sven Panne.  Previously only 4 args were supported.
parent 541d1d89
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ghc/rts/Adjustor.c
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......@@ -40,6 +40,7 @@ Haskell side.
#include "Rts.h"
#include "RtsUtils.h"
#include "RtsFlags.h"
#include <stdlib.h>
/* Heavily arch-specific, I'm afraid.. */
......@@ -156,92 +157,68 @@ createAdjustor(int cconv, StgStablePtr hptr, StgFunPtr wptr)
adj_code[0x10] = (unsigned char)0xe0;
}
#elif defined(sparc_TARGET_ARCH)
/* Magic constant computed by inspecting the code length of
the following assembly language snippet
(offset and machine code prefixed):
<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]
<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.
Input paramters and results are passed via registers. (%o0 in the
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).
SUP, 25 Apr 02: We are quite lucky to push a multiple of 8 bytes in
front of the existing arguments, because %sp must stay double-word
aligned at all times, see: http://www.sparc.org/standards/psABI3rd.pdf
Although we extend the *caller's* stack frame, this shouldn't cause
any problems for a C-like caller: alloca is implemented similarly, and
local variables should be accessed via %fp, not %sp. In a nutshell:
This should work. (Famous last words! :-)
/* Magic constant computed by inspecting the code length of the following
assembly language snippet (offset and machine code prefixed):
<00>: 9C23A008 sub %sp, 8, %sp ! make room for %o4/%o5 in caller's frame
<04>: DA23A060 st %o5, [%sp + 96] ! shift registers by 2 positions
<08>: D823A05C st %o4, [%sp + 92]
<0C>: 9A10000B mov %o3, %o5
<10>: 9810000A mov %o2, %o4
<14>: 96100009 mov %o1, %o3
<18>: 94100008 mov %o0, %o2
<1C>: 13000000 sethi %hi(wptr), %o1 ! load up wptr (1 of 2)
<20>: 11000000 sethi %hi(hptr), %o0 ! load up hptr (1 of 2)
<24>: 81C26000 jmp %o1 + %lo(wptr) ! jump to wptr (load 2 of 2)
<28>: 90122000 or %o0, %lo(hptr), %o0 ! load up hptr (2 of 2, delay slot)
<2C> 00000000 ! place for getting hptr back easily
ccall'ing on SPARC is easy, because we are quite lucky to push a
multiple of 8 bytes (1 word hptr + 1 word dummy arg) in front of the
existing arguments (note that %sp must stay double-word aligned at
all times, see ABI spec at http://www.sparc.org/standards/psABI3rd.pdf).
To do this, we extend the *caller's* stack frame by 2 words and shift
the output registers used for argument passing (%o0 - %o5, we are a *leaf*
procedure because of the tail-jump) by 2 positions. This makes room in
%o0 and %o1 for the additinal arguments, namely hptr and a dummy (used
for destination addr of jump on SPARC, return address on x86, ...). This
shouldn't cause any problems for a C-like caller: alloca is implemented
similarly, and local variables should be accessed via %fp, not %sp. In a
nutshell: This should work! (Famous last words! :-)
*/
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 */
adj_code[4] = (unsigned long)0x13000000;
adj_code[4] |= ((unsigned long)wptr) >> 10;
/* sethi %hi(hptr), %o0 */
adj_code[5] = (unsigned long)0x11000000;
adj_code[5] |= ((unsigned long)hptr) >> 10;
/* jmp %o1+%lo(wptr) */
adj_code[6] = (unsigned long)0x81c26000;
adj_code[6] |= ((unsigned long)wptr) & 0x000003ff;
/* or %o0, %lo(hptr), %o0 */
adj_code[7] = (unsigned long)0x90122000;
adj_code[7] |= ((unsigned long)hptr) & 0x000003ff;
adj_code[8] = (StgStablePtr)hptr;
/* flush cache */
asm("flush %0" : : "r" (adj_code ));
asm("flush %0" : : "r" (adj_code + 2));
asm("flush %0" : : "r" (adj_code + 4));
asm("flush %0" : : "r" (adj_code + 6));
/* max. 5 instructions latency, and we need at >= 1 for returning */
asm("nop");
asm("nop");
asm("nop");
asm("nop");
if ((adjustor = stgMallocBytes(4*(11+1), "createAdjustor")) != NULL) {
unsigned long *const adj_code = (unsigned long *)adjustor;
adj_code[ 0] = 0x9C23A008UL; /* sub %sp, 8, %sp */
adj_code[ 1] = 0xDA23A060UL; /* st %o5, [%sp + 96] */
adj_code[ 2] = 0xD823A05CUL; /* st %o4, [%sp + 92] */
adj_code[ 3] = 0x9A10000BUL; /* mov %o3, %o5 */
adj_code[ 4] = 0x9810000AUL; /* mov %o2, %o4 */
adj_code[ 5] = 0x96100009UL; /* mov %o1, %o3 */
adj_code[ 6] = 0x94100008UL; /* mov %o0, %o2 */
adj_code[ 7] = 0x13000000UL; /* sethi %hi(wptr), %o1 */
adj_code[ 7] |= ((unsigned long)wptr) >> 10;
adj_code[ 8] = 0x11000000UL; /* sethi %hi(hptr), %o0 */
adj_code[ 8] |= ((unsigned long)hptr) >> 10;
adj_code[ 9] = 0x81C26000UL; /* jmp %o1 + %lo(wptr) */
adj_code[ 9] |= ((unsigned long)wptr) & 0x000003FFUL;
adj_code[10] = 0x90122000UL; /* or %o0, %lo(hptr), %o0 */
adj_code[10] |= ((unsigned long)hptr) & 0x000003FFUL;
adj_code[11] = (unsigned long)hptr;
/* flush cache */
asm("flush %0" : : "r" (adj_code ));
asm("flush %0" : : "r" (adj_code + 2));
asm("flush %0" : : "r" (adj_code + 4));
asm("flush %0" : : "r" (adj_code + 6));
asm("flush %0" : : "r" (adj_code + 10));
/* max. 5 instructions latency, and we need at >= 1 for returning */
asm("nop");
asm("nop");
asm("nop");
asm("nop");
}
#elif defined(alpha_TARGET_ARCH)
/* Magic constant computed by inspecting the code length of
......@@ -396,13 +373,13 @@ freeHaskellFunctionPtr(void* ptr)
freeStablePtr(*((StgStablePtr*)((unsigned char*)ptr + 0x02)));
}
#elif defined(sparc_TARGET_ARCH)
if ( *(unsigned long*)ptr != 0x9A10000B ) {
if ( *(unsigned long*)ptr != 0x9C23A008UL ) {
fprintf(stderr, "freeHaskellFunctionPtr: not for me, guv! %p\n", ptr);
return;
}
/* Free the stable pointer first..*/
freeStablePtr(*((StgStablePtr*)((unsigned long*)ptr + 8)));
freeStablePtr(*((StgStablePtr*)((unsigned long*)ptr + 11)));
#elif defined(alpha_TARGET_ARCH)
if ( *(StgWord64*)ptr != 0xa77b0018a61b0010L ) {
fprintf(stderr, "freeHaskellFunctionPtr: not for me, guv! %p\n", ptr);
......
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