Date: Thu, 22 Nov 2018 13:03:11 +0000 (UTC) From: Marius Strobl <marius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r340759 - stable/12/sys/sparc64/sparc64 Message-ID: <201811221303.wAMD3BPr071746@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: marius Date: Thu Nov 22 13:03:11 2018 New Revision: 340759 URL: https://svnweb.freebsd.org/changeset/base/340759 Log: MFC: r340656 Given that the idea of D15374 was to "make memmove a first class citizen", provide a _MEMMOVE extension of _MEMCPY that deals with overlap based on the previous bcopy(9) implementation and use the former for bcopy(9) and memmove(9). This addresses my D15374 review comment, avoiding extra MOVs in case of memmove(9) and trashing the stack pointer. Modified: stable/12/sys/sparc64/sparc64/support.S Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/sparc64/sparc64/support.S ============================================================================== --- stable/12/sys/sparc64/sparc64/support.S Thu Nov 22 09:47:51 2018 (r340758) +++ stable/12/sys/sparc64/sparc64/support.S Thu Nov 22 13:03:11 2018 (r340759) @@ -207,6 +207,30 @@ __FBSDID("$FreeBSD$"); 6: /* + * Extension of _MEMCPY dealing with overlap, but unaware of ASIs. + * Used for bcopy() and memmove(). + */ +#define _MEMMOVE(dst, src, len) \ + /* Check for overlap, and copy backwards if so. */ \ + sub dst, src, %g1 ; \ + cmp %g1, len ; \ + bgeu,a,pt %xcc, 2f ; \ + nop ; \ + /* Copy backwards. */ \ + add src, len, src ; \ + add dst, len, dst ; \ +1: deccc 1, len ; \ + bl,pn %xcc, 3f ; \ + dec 1, src ; \ + ldub [src], %g1 ; \ + dec 1, dst ; \ + ba %xcc, 1b ; \ + stb %g1, [dst] ; \ +2: /* Do the fast version. */ \ + _MEMCPY(dst, src, len, EMPTY, EMPTY, EMPTY, EMPTY) ; \ +3: + +/* * void ascopy(u_long asi, vm_offset_t src, vm_offset_t dst, size_t len) */ ENTRY(ascopy) @@ -265,49 +289,14 @@ ENTRY(bcmp) END(bcmp) /* - * void *memmove(void *dst, const void *src, size_t len) * void bcopy(const void *src, void *dst, size_t len) */ -ENTRY(memmove) - /* - * Swap src/dst for memmove/bcopy differences - */ - mov %o0, %o6 - mov %o1, %o0 - mov %o6, %o1 -ALTENTRY(bcopy) - /* - * Check for overlap, and copy backwards if so. - */ - sub %o1, %o0, %g1 - cmp %g1, %o2 - bgeu,a,pt %xcc, 3f +ENTRY(bcopy) + _MEMMOVE(%o1, %o0, %o2) + retl nop +END(bcopy) - /* - * Copy backwards. - */ - add %o0, %o2, %o0 - add %o1, %o2, %o1 -1: deccc 1, %o2 - bl,a,pn %xcc, 2f - nop - dec 1, %o0 - ldub [%o0], %g1 - dec 1, %o1 - ba %xcc, 1b - stb %g1, [%o1] -2: retl - mov %o6, %o0 - - /* - * Do the fast version. - */ -3: _MEMCPY(%o1, %o0, %o2, EMPTY, EMPTY, EMPTY, EMPTY) - retl - mov %o6, %o0 -END(memmove) - /* * void bzero(void *b, size_t len) */ @@ -335,6 +324,16 @@ ENTRY(memcpy) retl nop END(memcpy) + +/* + * void *memmove(void *dst, const void *src, size_t len) + */ +ENTRY(memmove) + mov %o0, %o3 + _MEMMOVE(%o3, %o1, %o2) + retl + nop +END(memmove) /* * void *memset(void *b, int c, size_t len)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201811221303.wAMD3BPr071746>