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Update for AMD64-style syscalls. Repocopied from i386/SYS.h.

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Note that the syscall instruction clobbers %rcx, which is inconvenient
because it is the fourth syscall argument, so we use %r10 (another scratch
register) for the 4th syscall arg instead (I picked %r10 to be the same as
NetBSD).  int 0x80 is still possible though, and it uses %rcx as usual.
Note that the syscall style syscall does *NOT* preserve all the registers,
unlike int 0x80.  We do not preserve the scratch registers except for
%rdi and %rsi.  int 0x80 does preserve everything but the return values.
This commit is contained in:
Peter Wemm 2003-04-30 18:06:14 +00:00
parent d90e753aa8
commit 4dbb9c65d7
1 changed files with 4 additions and 7 deletions
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11
lib/libc/amd64/SYS.h
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@ -40,22 +40,19 @@
#include <sys/syscall.h>
#include <machine/asm.h>
#define SYSCALL(x) 2: PIC_PROLOGUE; jmp PIC_PLT(HIDENAME(cerror)); \
#define SYSCALL(x) 2: jmp PIC_PLT(HIDENAME(cerror)); \
ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(x); \
.set CNAME(x),CNAME(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
mov __CONCAT($SYS_,x),%eax; KERNCALL; jb 2b
mov __CONCAT($SYS_,x),%rax; KERNCALL; jb 2b
#define RSYSCALL(x) SYSCALL(x); ret
#define PSEUDO(x) ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
mov __CONCAT($SYS_,x),%eax; KERNCALL; ret
mov __CONCAT($SYS_,x),%rax; KERNCALL; ret
/* gas messes up offset -- although we don't currently need it, do for BCS */
#define LCALL(x,y) .byte 0x9a ; .long y; .word x
#define KERNCALL int $0x80
#define KERNCALL movq %rcx, %r10; syscall