Setjmp/longjmp updates and cleanup.
This commit is contained in:
David van Moolenbroek
@@ -1,87 +0,0 @@
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/* This file is intended for use by assembly language programs that
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* need to manipulate a jmp_buf. It may only be used by those systems
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* for which a jmp_buf is identical to a struct sigcontext.
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*/
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#ifndef _JMP_BUF_H
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#define _JMP_BUF_H
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#if !defined(CHIP)
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#include "error, configuration is not known"
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#endif
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#if (CHIP == INTEL)
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#if _WORD_SIZE == 4
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#define JB_FLAGS 0
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#define JB_MASK 4
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#define JB_GS 8
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#define JB_FS 10
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#define JB_ES 12
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#define JB_DS 14
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#define JB_DI 16
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#define JB_SI 20
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#define JB_BP 24
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#define JB_ST 28
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#define JB_BX 32
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#define JB_DX 36
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#define JB_CX 40
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#define JB_AX 44
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#define JB_RETADR 48
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#define JB_IP 52
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#define JB_CS 56
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#define JB_PSW 60
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#define JB_SP 64
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#define JB_SS 68
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#else /* _WORD_SIZE == 2 */
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#define JB_FLAGS 0
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#define JB_MASK 2
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#define JB_ES 6
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#define JB_DS 8
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#define JB_DI 10
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#define JB_SI 12
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#define JB_BP 14
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#define JB_ST 16
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#define JB_BX 18
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#define JB_DX 20
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#define JB_CX 22
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#define JB_AX 24
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#define JB_RETADR 26
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#define JB_IP 28
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#define JB_CS 30
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#define JB_PSW 32
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#define JB_SP 34
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#define JB_SS 36
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#endif /* _WORD_SIZE == 2 */
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#else /* !(CHIP == INTEL) */
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#if (CHIP == M68000)
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#define JB_FLAGS 0
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#define JB_MASK 2
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#define JB_RETREG 6
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#define JB_D1 10
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#define JB_D2 14
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#define JB_D3 18
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#define JB_D4 22
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#define JB_D5 26
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#define JB_D6 20
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#define JB_D7 34
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#define JB_A0 38
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#define JB_A1 42
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#define JB_A2 46
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#define JB_A3 50
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#define JB_A4 54
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#define JB_A5 58
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#define JB_A6 62
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#define JB_SP 66
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#define JB_PC 70
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#define JB_PSW 74
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#else /* !(CHIP == INTEL) && !(CHIP == M68000) */
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#include "error, CHIP is not supported"
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#endif /* (CHIP == INTEL) */
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/* Defines from C headers needed in assembly code. The headers have too
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* much C stuff to used directly.
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*/
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#define SIG_BLOCK 0 /* must agree with <signal.h> */
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#define SC_SIGCONTEXT 2 /* must agree with <sys/sigcontext.h> */
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#define SC_NOREGLOCALS 4 /* must agree with <sys/sigcontext.h> */
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#endif /* _JMP_BUF_H */
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158
include/setjmp.h
158
include/setjmp.h
@@ -1,67 +1,51 @@
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/* The <setjmp.h> header relates to the C phenomenon known as setjmp/longjmp.
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* It is used to escape out of the current situation into a previous one.
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* A typical example is in an editor, where hitting DEL breaks off the current
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* command and puts the editor back in the main loop, though care has to be
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* taken when the DEL occurs while executing a library function, since
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* some of them are not reentrant.
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*
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* POSIX does not require the process signal mask to be saved and restored
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* during setjmp/longjmp. However, the current implementation does this
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* in order to agree with OSF/1 and other BSD derived systems.
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* The actual implementations of all these functions and, by extension, parts
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* of this header, are both compiler- and architecture-dependent. Currently
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* two compilers are supported: ACK and GCC. Each of these has their own
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* implementation of the functions in their runtime system library code.
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* As it is impossible to predict the requirements for any other compilers,
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* this header may not be compatible with such other compilers either.
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*
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* The pair of functions _setjmp/_longjmp may be used when the signal
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* mask is not to be saved/restored. These functions are traditional
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* in BSD systems.
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* The ACK compiler will not enregister any variables inside a function
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* containing a setjmp call, even if those variables are explicitly declared
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* as register variables. Thus for ACK, of all the registers, only the
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* program counter, stack pointer and frame pointer have to be saved into the
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* jmp_buf structure. This makes the jmp_buf structure very small, and
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* moreover, the implementation of the setjmp/longjmp calls (written in EM)
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* architecture-independent and thus very portable. The ACK compiler
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* recognizes only the symbol __setjmp as being such a setjmp call.
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*
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* There are different ways of implementing setjmp/longjmp. Probably
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* the best way is to unify it with signal handling. This is true for the
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* following reasons: Both setjmp/longjmp and signal delivery must save
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* a context so that it may be restored later. The jmp_buf necessarily
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* contains signal information, namely the signal mask to restore. Both
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* longjmp and the return of a signal handler must trap to the operating
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* system to restore the previous signal mask. Finally, the jmp_buf
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* and the sigcontext structure contain the registers to restore.
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* The GCC compiler recognizes all of the setjmp/_setjmp/__setjmp name
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* variants as calls to setjmp functions, and treats them as special
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* accordingly, but does require that the setjmp implementation save and
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* restore most of the registers. It has no portable setjmp and longjmp
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* functions like ACK, and therefore has to have enough space in the jmp_buf
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* structure to store the registers on any architecture it's ported to.
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*
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* Some compilers, namely ACK, will not enregister any variables inside a
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* function containing a call to setjmp, even if those variables are
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* explicitly declared as register variables. Thus for ACK, the
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* identification of the jmp_buf with a sigcontext structure would cause
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* unnecessary overhead: the jmp_buf has room for all the registers, but
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* the only registers that need to be saved are the stack pointer,
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* frame pointer, and program counter.
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* Taking the common denominator of both compilers, the function definitions
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* in this header rely on the presence of merely two functions: __setjmp and
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* longjmp. On the other hand, the size of jmp_buf depends on the compiler
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* used: for ACK, jmp_buf is exactly big enough to store the three mentioned
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* registers; for GCC and any other compiler, the size is chosen in such a
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* way that it's likely to offer enough room to store registers for any
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* architecture. The POSIX sigjmp_buf is identical to jmp_buf in all cases.
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*
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* So, for ACK a jmp_buf is much smaller than a sigcontext structure, and
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* longjmp does not directly call sigreturn. Instead, longjmp calls a
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* front-end function which initializes the appropriate fields of a
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* sigcontext structure, marks this structure as containing no valid
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* general purpose registers, and then calls sigreturn.
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* As far as porting is concerned --
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*
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* The POSIX sigjmp_buf is identical to the jmp_buf in all cases.
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* All code writers/porters that have to deal with the actual contents of the
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* jmp_buf structure in one way or another, should look at <sys/jmp_buf.h>.
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*
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* Different compilers have different symbols that they recognize as
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* setjmp symbols. ACK recognizes __setjmp, the GNU C compiler
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* recognizes setjmp and _setjmp, and BCC recognizes all three.
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* When these symbols occur within a function, the compiler may keep
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* all local variables on the stack, avoid certain optimizations, or
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* pass hidden arguments to the setjmp function.
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*
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* Thus, setjmp implementations vary in two independent ways which may
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* be identified through the following preprocessor tokens:
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* Porters of a new compiler to Minix have to make sure the compiler
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* recognizes at least __setjmp as a setjmp call (if applicable) and provide
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* library implementations of __setjmp and longjmp conforming to their
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* declarations below; if this is not possible, compiler-specific code will
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* have to be added to this header.
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*
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* _SETJMP_SYMBOL -- If 0, this means the compiler treats setjmp and _setjmp
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* specially. If 1, this means the compiler treats __setjmp specially.
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*
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* _SETJMP_SAVES_REGS -- If 1, this means setjmp/longjmp must explicitly
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* save and restore all registers. This also implies that a jmp_buf is
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* different than a sigcontext structure. If 0, this means that the compiler
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* will not use register variables within a function that calls one of
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* its SETJMP_SYMBOLs.
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*
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* When _SETJMP_SYMBOL = 1, the implementation has a few dozen bytes of
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* unnecessary overhead. This happens in the following manner: a program uses
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* _setjmp/_longjmp because it is not interested in saving and restoring the
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* signal mask. Nevertheless, because _setjmp expands to the general purpose
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* function __setjmp, code for sigprocmask(2) is linked into the program.
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* Porters of Minix+GCC to other architectures have to make sure that the
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* __regs array of the jmp_buf structure is large enough to hold all the
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* registers the __setjmp implementation for that architecture has to save.
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*/
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#ifndef _SETJMP_H
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@@ -71,82 +55,34 @@
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#include <ansi.h>
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#endif
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#if !defined(__ACK__) && !defined(__BCC__) && !defined(__GNUC__)
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#define __ACK__
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#endif
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#ifdef __ACK__
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#define _SETJMP_SYMBOL 1
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#define _SETJMP_SAVES_REGS 0
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#endif
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#ifdef __BCC__
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#define _SETJMP_SYMBOL 0
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#define _SETJMP_SAVES_REGS 1
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#endif
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#ifdef __GNUC__
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#define _SETJMP_SYMBOL 1
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#define _SETJMP_SAVES_REGS 1
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#endif
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/* The jmp_buf data type. Do not change the order of these fields -- some
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* C library code refers to these fields by name. When _SETJMP_SAVES_REGS
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* is 1, the file <sys/jmp_buf.h> gives the usage of the sixteen registers.
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*/
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typedef struct {
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int __flags; /* XXX - long might give better alignment */
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long __mask; /* must have size >= sizeof(sigset_t) */
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#if (_SETJMP_SAVES_REGS == 0)
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#if defined(__ACK__)
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_PROTOTYPE(void (*__pc),(void)); /* program counter */
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void *__sp; /* stack pointer */
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void *__lb; /* local base (ACKspeak for frame pointer) */
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#else
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void *__regs[16]; /* size is machine dependent */
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long __mask; /* must have size >= sizeof(sigset_t) */
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int __flags;
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#else /* GCC */
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int __flags; /* XXX - long might give better alignment */
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long __mask; /* must have size >= sizeof(sigset_t) */
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void *__regs[16]; /* actual use is architecture dependent */
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#endif
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} jmp_buf[1];
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#if (_SETJMP_SYMBOL == 1)
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_PROTOTYPE( int __setjmp, (jmp_buf _env, int _savemask) );
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_PROTOTYPE( void longjmp, (jmp_buf _env, int _val) );
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_PROTOTYPE(int sigjmp, (jmp_buf _jb, int _retval) );
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#define setjmp(env) __setjmp((env), 1)
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#ifdef _MINIX
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#define _setjmp(env) __setjmp((env), 0)
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_PROTOTYPE(void _longjmp, (jmp_buf _env, int _val) );
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#define _longjmp(env, val) longjmp((env), (val))
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#endif
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#ifdef _POSIX_SOURCE
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typedef jmp_buf sigjmp_buf;
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#ifdef __GNUC__
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#define siglongjmp longjmp
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#else
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_PROTOTYPE( void siglongjmp, (sigjmp_buf _env, int _val) );
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#endif
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#define sigsetjmp(env, savemask) __setjmp((env), (savemask))
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#define siglongjmp(env, val) longjmp((env), (val))
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#endif /* _POSIX_SOURCE */
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#endif /* _SETJMP_SYMBOL == 1 */
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#if (_SETJMP_SYMBOL == 0)
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_PROTOTYPE( int setjmp, (jmp_buf _env) );
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_PROTOTYPE( void longjmp, (jmp_buf _env, int _val) );
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#ifdef _MINIX
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_PROTOTYPE( int _setjmp, (jmp_buf _env) );
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_PROTOTYPE( void _longjmp, (jmp_buf _env, int _val) );
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#endif
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#ifdef _POSIX_SOURCE
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#define sigjmp_buf jmp_buf
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_PROTOTYPE( void siglongjmp, (sigjmp_buf _env, int _val) );
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/* XXX - the name _setjmp is no good - that's why ACK used __setjmp. */
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#define sigsetjmp(env, savemask) ((savemask) ? setjmp(env) : _setjmp(env))
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#endif /* _POSIX_SOURCE */
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#endif /* _SETJMP_SYMBOL == 0 */
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#endif /* _SETJMP_H */
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45
include/sys/jmp_buf.h
Normal file
45
include/sys/jmp_buf.h
Normal file
@@ -0,0 +1,45 @@
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/* This file is intended for use by program code (possibly written in
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* assembly) that needs to manipulate a jmp_buf or sigjmp_buf. The JB_*
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* values are byte offsets into the jmp_buf and sigjmp_buf structures.
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*/
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#ifndef _JMP_BUF_H
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#define _JMP_BUF_H
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#include <minix/config.h>
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#if defined(__ACK__)
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/* as per lib/ack/rts/setjmp.e */
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/* note the lack of parentheses, which would confuse 'as' */
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#define JB_PC 0
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#define JB_SP JB_PC + _EM_PSIZE
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#define JB_LB JB_SP + _EM_PSIZE
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#define JB_MASK JB_LB + _EM_PSIZE
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#define JB_FLAGS JB_MASK + _EM_LSIZE
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#if (CHIP == INTEL)
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#define JB_BP JB_LB
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#endif
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#elif defined(__GNUC__)
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#if (CHIP == INTEL) && (_WORD_SIZE == 4)
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/* as per lib/gnu/rts/__setjmp.gs */
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#define JB_FLAGS 0
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#define JB_MASK 4
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#define JB_PC 8
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#define JB_SP 12
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#define JB_BP 16
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#define JB_BX 20
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#define JB_CX 24
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#define JB_DX 28
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#define JB_SI 32
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#define JB_DI 36
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#endif /* (CHIP == INTEL) && (_WORD_SIZE == 4) */
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#endif /* __GNU__ */
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#endif /* _JMP_BUF_H */
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@@ -136,11 +136,6 @@ struct sigcontext {
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#define sc_psw sc_regs.sr_psw
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#endif /* _MINIX_CHIP == M68000 */
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/* Values for sc_flags. Must agree with <minix/jmp_buf.h>. */
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#define SC_SIGCONTEXT 2 /* nonzero when signal context is included */
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#define SC_NOREGLOCALS 4 /* nonzero when registers are not to be
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saved and restored */
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_PROTOTYPE( int sigreturn, (struct sigcontext *_scp) );
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#endif /* _SIGCONTEXT_H */
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