#define OP_LO(op,lo) ((((unsigned)(op)) << 16) | (((unsigned)(lo)) & 0xFFFF))
#define OP_HI(op,hi) ((((unsigned)(op)) << 16) | (((unsigned)(hi)) >> 16))
- {
- AdjustorStub *adjustorStub;
- int sz = 0, extra_sz, total_sz;
-
- // from AdjustorAsm.s
- // not declared as a function so that AIX-style
- // fundescs can never get in the way.
- extern void *adjustorCode;
-
+ {
+ /* The following code applies to all PowerPC and PowerPC64 platforms
+ whose stack layout is based on the AIX ABI.
+
+ Besides (obviously) AIX, this includes
+ Mac OS 9 and BeOS/PPC (may they rest in peace),
+ which use the 32-bit AIX ABI
+ powerpc64-linux,
+ which uses the 64-bit AIX ABI
+ and Darwin (Mac OS X),
+ which uses the same stack layout as AIX,
+ but no function descriptors.
+
+ The actual stack-frame shuffling is implemented out-of-line
+ in the function adjustorCode, in AdjustorAsm.S.
+ Here, we set up an AdjustorStub structure, which
+ is a function descriptor (on platforms that have function
+ descriptors) or a short piece of stub code (on Darwin) to call
+ adjustorCode with a pointer to the AdjustorStub struct loaded
+ into register r2.
+
+ One nice thing about this is that there is _no_ code generated at
+ runtime on the platforms that have function descriptors.
+ */
+ AdjustorStub *adjustorStub;
+ int sz = 0, extra_sz, total_sz;
+
+ // from AdjustorAsm.s
+ // not declared as a function so that AIX-style
+ // fundescs can never get in the way.
+ extern void *adjustorCode;
+
#ifdef FUNDESCS
- adjustorStub = stgMallocBytes(sizeof(AdjustorStub), "createAdjustor");
+ adjustorStub = stgMallocBytes(sizeof(AdjustorStub), "createAdjustor");
#else
- adjustorStub = mallocBytesRWX(sizeof(AdjustorStub));
+ adjustorStub = mallocBytesRWX(sizeof(AdjustorStub));
#endif
- adjustor = adjustorStub;
-
- adjustorStub->code = (void*) &adjustorCode;
+ adjustor = adjustorStub;
+
+ adjustorStub->code = (void*) &adjustorCode;
#ifdef FUNDESCS
- // function descriptors are a cool idea.
- // We don't need to generate any code at runtime.
- adjustorStub->toc = adjustorStub;
+ // function descriptors are a cool idea.
+ // We don't need to generate any code at runtime.
+ adjustorStub->toc = adjustorStub;
#else
- // no function descriptors :-(
- // We need to do things "by hand".
+ // no function descriptors :-(
+ // We need to do things "by hand".
#if defined(powerpc_TARGET_ARCH)
- // lis r2, hi(adjustorStub)
- adjustorStub->lis = OP_HI(0x3c40, adjustorStub);
- // ori r2, r2, lo(adjustorStub)
- adjustorStub->ori = OP_LO(0x6042, adjustorStub);
- // lwz r0, code(r2)
- adjustorStub->lwz = OP_LO(0x8002, (char*)(&adjustorStub->code)
- - (char*)adjustorStub);
- // mtctr r0
- adjustorStub->mtctr = 0x7c0903a6;
- // bctr
- adjustorStub->bctr = 0x4e800420;
+ // lis r2, hi(adjustorStub)
+ adjustorStub->lis = OP_HI(0x3c40, adjustorStub);
+ // ori r2, r2, lo(adjustorStub)
+ adjustorStub->ori = OP_LO(0x6042, adjustorStub);
+ // lwz r0, code(r2)
+ adjustorStub->lwz = OP_LO(0x8002, (char*)(&adjustorStub->code)
+ - (char*)adjustorStub);
+ // mtctr r0
+ adjustorStub->mtctr = 0x7c0903a6;
+ // bctr
+ adjustorStub->bctr = 0x4e800420;
#else
- barf("adjustor creation not supported on this platform");
+ barf("adjustor creation not supported on this platform");
#endif
- // Flush the Instruction cache:
+ // Flush the Instruction cache:
+ {
+ int n = sizeof(AdjustorStub)/sizeof(unsigned);
+ unsigned *p = (unsigned*)adjustor;
+ while(n--)
{
- int n = sizeof(AdjustorStub)/sizeof(unsigned);
- unsigned *p = (unsigned*)adjustor;
- while(n--)
- {
- __asm__ volatile ("dcbf 0,%0\n\tsync\n\ticbi 0,%0"
- : : "r" (p));
- p++;
- }
- __asm__ volatile ("sync\n\tisync");
+ __asm__ volatile ("dcbf 0,%0\n\tsync\n\ticbi 0,%0"
+ : : "r" (p));
+ p++;
}
+ __asm__ volatile ("sync\n\tisync");
+ }
#endif
- printf("createAdjustor: %s\n", typeString);
- while(*typeString)
- {
- char t = *typeString++;
+ // Calculate the size of the stack frame, in words.
+ while(*typeString)
+ {
+ char t = *typeString++;
- switch(t)
- {
-#if defined(powerpc64_TARGET_ARCH)
- case 'd': sz += 1; break;
- case 'l': sz += 1; break;
-#else
- case 'd': sz += 2; break;
- case 'l': sz += 2; break;
+ switch(t)
+ {
+#if defined(powerpc_TARGET_ARCH)
+ // on 32-bit platforms, Double and Int64 occupy two words.
+ case 'd':
+ case 'l':
+ sz += 2;
+ break;
#endif
- case 'f': sz += 1; break;
- case 'i': sz += 1; break;
- }
+ // everything else is one word.
+ default:
+ sz += 1;
}
- extra_sz = sz - 8;
- if(extra_sz < 0)
- extra_sz = 0;
- total_sz = (6 /* linkage area */
- + 8 /* minimum parameter area */
- + 2 /* two extra arguments */
- + extra_sz)*sizeof(StgWord);
-
- // align to 16 bytes.
- // AIX only requires 8 bytes, but who cares?
- total_sz = (total_sz+15) & ~0xF;
-
- adjustorStub->hptr = hptr;
- adjustorStub->wptr = wptr;
- adjustorStub->negative_framesize = -total_sz;
- adjustorStub->extrawords_plus_one = extra_sz + 1;
}
+ // The first eight words of the parameter area
+ // are just "backing store" for the parameters passed in
+ // the GPRs. extra_sz is the number of words beyond those first
+ // 8 words.
+ extra_sz = sz - 8;
+ if(extra_sz < 0)
+ extra_sz = 0;
+
+ // Calculate the total size of the stack frame.
+ total_sz = (6 /* linkage area */
+ + 8 /* minimum parameter area */
+ + 2 /* two extra arguments */
+ + extra_sz)*sizeof(StgWord);
+
+ // align to 16 bytes.
+ // AIX only requires 8 bytes, but who cares?
+ total_sz = (total_sz+15) & ~0xF;
+
+ // Fill in the information that adjustorCode in AdjustorAsm.S
+ // will use to create a new stack frame with the additional args.
+ adjustorStub->hptr = hptr;
+ adjustorStub->wptr = wptr;
+ adjustorStub->negative_framesize = -total_sz;
+ adjustorStub->extrawords_plus_one = extra_sz + 1;
+ }
#elif defined(ia64_TARGET_ARCH)
/*
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