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764 |
jeremybenn |
/* descriptor-pa32-hpux.h - Given a function pointer, extract and return the
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actual code address of the corresponding function.
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This is done by checking if the plabel bit is set. If it's not set,
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return the function pointer. If it's set, mask it off and extract
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the address from the function descriptor. This address may point
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to an export stub. If so, extract the branch target from the stub
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and return it. Otherwise, the address from the function descriptor
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is returned.
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Copyright (C) 2006 Free Software Foundation
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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#define UNWRAP_FUNCTION_DESCRIPTOR pa_unwrap_function_descriptor
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Extract bit field from word using HP's numbering (MSB = 0). */
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#define GET_FIELD(X, FROM, TO) \
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((X) >> (31 - (TO)) & ((1 << ((TO) - (FROM) + 1)) - 1))
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static inline int
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sign_extend (int x, int len)
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{
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int signbit = (1 << (len - 1));
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int mask = (signbit << 1) - 1;
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return ((x & mask) ^ signbit) - signbit;
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}
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/* Extract a 17-bit signed constant from branch instructions. */
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static inline int
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extract_17 (unsigned word)
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{
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return sign_extend (GET_FIELD (word, 19, 28)
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| GET_FIELD (word, 29, 29) << 10
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| GET_FIELD (word, 11, 15) << 11
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| (word & 0x1) << 16, 17);
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}
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/* Extract a 22-bit signed constant from branch instructions. */
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static inline int
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extract_22 (unsigned word)
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{
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return sign_extend (GET_FIELD (word, 19, 28)
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| GET_FIELD (word, 29, 29) << 10
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| GET_FIELD (word, 11, 15) << 11
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| GET_FIELD (word, 6, 10) << 16
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| (word & 0x1) << 21, 22);
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}
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static void *
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pa_unwrap_function_descriptor (void *addr)
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{
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unsigned int *tmp_addr;
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/* Check if plabel bit is set in function pointer. */
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if (!((unsigned int) addr & 2))
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return addr;
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tmp_addr = *(unsigned int **) ((unsigned int) addr & ~3);
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/* If TMP_ADDR points to an export stub, adjust it so that it points
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to the branch target of the stub. */
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if ((*tmp_addr & 0xffe0e002) == 0xe8400000 /* bl x,r2 */
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&& *(tmp_addr + 1) == 0x08000240 /* nop */
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&& *(tmp_addr + 2) == 0x4bc23fd1 /* ldw -18(sp),rp */
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&& *(tmp_addr + 3) == 0x004010a1 /* ldsid (rp),r1 */
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&& *(tmp_addr + 4) == 0x00011820 /* mtsp r1,sr0 */
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&& *(tmp_addr + 5) == 0xe0400002) /* be,n 0(sr0,rp) */
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/* Extract target address from PA 1.x 17-bit branch. */
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tmp_addr += extract_17 (*tmp_addr) + 2;
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else if ((*tmp_addr & 0xfc00e002) == 0xe800a000 /* b,l x,r2 */
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&& *(tmp_addr + 1) == 0x08000240 /* nop */
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&& *(tmp_addr + 2) == 0x4bc23fd1 /* ldw -18(sp),rp */
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&& *(tmp_addr + 3) == 0xe840d002) /* bve,n (rp) */
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/* Extract target address from PA 2.0 22-bit branch. */
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tmp_addr += extract_22 (*tmp_addr) + 2;
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return (void *) tmp_addr;
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}
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#ifdef __cplusplus
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}
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#endif
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