From faec4d69bc0cc7ee979c3f45c7d5f09f01198c1a Mon Sep 17 00:00:00 2001 From: sewardj Date: Wed, 22 Aug 2001 14:32:19 +0000 Subject: [PATCH] [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. --- ghc/rts/Adjustor.c | 60 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 44 insertions(+), 16 deletions(-) diff --git a/ghc/rts/Adjustor.c b/ghc/rts/Adjustor.c index 4d6c223..8f12e84 100644 --- 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): - <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] - <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. @@ -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. + + 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 */ - *((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 */ - *((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) */ - *((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 */ - *((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 -- 1.7.10.4