The attached diff shaves four bytes
from every syscall wrapper (e.g., __sys_write, etc.)
In looking carefully at library sizes, I became
curious why a simple system call required 20
bytes; turns out a lot
of that was alignment padding.
Tim Kientzle
Index: lib/libc/i386/SYS.h
===================================================================
RCS file: /mnt/cvs/src/lib/libc/i386/SYS.h,v
retrieving revision 1.24
diff -c -r1.24 SYS.h
*** lib/libc/i386/SYS.h 17 Sep 2002 01:48:51 -0000 1.24
--- lib/libc/i386/SYS.h 8 Nov 2002 06:15:21 -0000
***************
*** 48,54 ****
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
mov __CONCAT($SYS_,x),%eax; KERNCALL; jb 2b
! #define RSYSCALL(x) SYSCALL(x); ret
#define PSEUDO(x) ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
--- 48,63 ----
.set CNAME(__CONCAT(_,x)),CNAME(__CONCAT(__sys_,x)); \
mov __CONCAT($SYS_,x),%eax; KERNCALL; jb 2b
! /* Version 1: More compact source */
! /* #define RSYSCALL(x) SYSCALL(x); ret */
! /* Version 2: More compact object code (fewer alignment requirements) */
! #define RSYSCALL(x) 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 2f; ret; \
! 2: PIC_PROLOGUE; jmp PIC_PLT(HIDENAME(cerror))
#define PSEUDO(x) ENTRY(__CONCAT(__sys_,x)); \
.weak CNAME(__CONCAT(_,x)); \
