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93 lines
3.1 KiB
PHP
93 lines
3.1 KiB
PHP
{
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This file is part of the Free Pascal run time library.
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Copyright (c) 2002 by Jonas Maebe and other members of the
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Free Pascal development team
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SetJmp and LongJmp implementation for exception handling
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See the file COPYING.FPC, included in this distribution,
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for details about the copyright.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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**********************************************************************}
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{#define ENV(base,reg) [%base + (reg * 4)]
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#define ST_FLUSH_WINDOWS 3
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#define RW_FP [%fp + 0x48]
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}
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procedure longjmp(var s : jmp_buf;value:longint);assembler;nostackframe;[Public,alias:'FPC_LONGJMP'];
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asm
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// Store our arguments in global registers so we can still
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// use them while unwinding frames and their register windows.
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ld [%o0+4], %g3 // Cache target FP in register %g3.
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mov %o0, %g1 // s in %g1
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orcc %o1, %g0, %g2 // value in %g2
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be,a .L0 // Branch if zero; else skip delay slot.
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mov 1, %g2 // Delay slot only hit if zero: VAL = 1.
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.L0:
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xor %fp, %g3, %o0
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add %fp, 512, %o1
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andncc %o0, 4095, %o0
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bne .Lthread
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cmp %o1, %g3
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bl .Lthread
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// Now we will loop, unwinding the register windows up the stack
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// until the restored %fp value matches the target value in %g3.
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.Lloop:
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cmp %fp, %g3 // Have we reached the target frame?
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bl,a .Lloop // Loop while current fp is below target.
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restore // Unwind register window in delay slot.
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be,a .Lfound // Better have hit it exactly.
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ld [%g1], %o0 // Delay slot: extract target SP.
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.Lthread:
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{
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* Do a "flush register windows trap". The trap handler in the
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* kernel writes all the register windows to their stack slots, and
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* marks them all as invalid (needing to be sucked up from the
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* stack when used). This ensures that all information needed to
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* unwind to these callers is in memory, not in the register
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* windows.
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}
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ta 3
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mov %g1,%o1 // use %o1, since %g1 will be destroyed by the call below
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ld [%o1], %fp // Set saved SP on restore below.
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sub %fp, 64, %sp // Allocate a register frame.
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st %g3, [%fp+48] // Set saved FP on restore below.
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ld [%o1+8], %o7 // Set return PC.
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retl
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restore %g2, 0, %o0 // Restore values from above register frame.
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.Lfound:
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// We have unwound register windows so %fp matches the target.
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mov %o0, %sp // OK, install new SP.
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.Lsp_ok:
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ld [%g1+8], %o0 // Extract target return PC.
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jmp %o0+8 // Return there.
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mov %g2, %o0 // Delay slot: set return value.
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end;
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function setjmp(var S:jmp_buf):longint;assembler;nostackframe;[Public,alias:'FPC_SETJMP'];
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asm
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// We don't create a stackframe so we can save PC,SP and FP of the caller
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st %o7, [%o0+8]
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st %sp, [%o0]
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st %fp, [%o0+4]
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ld [%o0+8], %o7
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mov %g0, %o0
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end;
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