diff options
Diffstat (limited to 'usr/klibc/arch/m68k/syscall.S')
| -rw-r--r-- | usr/klibc/arch/m68k/syscall.S | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/usr/klibc/arch/m68k/syscall.S b/usr/klibc/arch/m68k/syscall.S new file mode 100644 index 0000000..c909e2a --- /dev/null +++ b/usr/klibc/arch/m68k/syscall.S @@ -0,0 +1,53 @@ +/* + * arch/m68k/syscall.S + * + * Common tail-handling code for system calls. + * + * The arguments are on the stack; the system call number in %d0. + */ + + .text + .align 2 + .globl __syscall_common + .type __syscall_common, @function +__syscall_common: + /* + * According to eglibc, separate moves are faster than movem; + * speed is important and this code is not duplicated anyway, + * so we do the same here. We use %a1 as scratch register for + * saving; syscall arguments are to be in %d1 to %d5 and %a0. + */ + move.l 24(%sp), %a0 /* orig.sp+24: arg 6 */ + move.l %d5, -(%sp) /* push d5 (callee saved) */ + move.l 24(%sp), %d5 /* orig.sp+20: arg 5 */ + move.l %d4, -(%sp) /* push d4 (callee saved) */ + move.l 24(%sp), %d4 /* orig.sp+16: arg 4 */ + move.l %d3, -(%sp) /* push d3 (callee saved) */ + move.l 24(%sp), %d3 /* orig.sp+12: arg 3 */ + move.l %d2, %a1 /* save d2 (callee saved) in a1 */ + move.l 20(%sp), %d2 /* orig.sp+8: arg 2 */ + move.l 16(%sp), %d1 /* orig.sp+4: arg 1 */ + trap #0 + move.l %a1, %d2 /* restore d2 from a1 (scratch) */ + move.l (%sp)+, %d3 /* pop d3..d5, see above */ + move.l (%sp)+, %d4 + move.l (%sp)+, %d5 + + /* syscall is done, result in %d0, registers are restored */ + .globl __syscall_checkandout +__syscall_checkandout: + /* now check for error */ + cmp.l #-4095, %d0 + bcs.l 1f /* jump if _not_ error */ + + /* prepare for error return */ + neg.l %d0 + move.l %d0, (errno) + move.l #-1, %d0 + /* fallthrough into common return path */ + +1: /* copy return value to %a0 for syscalls returning pointers */ + move.l %d0, %a0 + rts + + .size __syscall_common,.-__syscall_common |