>From 07e5777f2de5a121273a7b4b8a933223f3dd813a Mon Sep 17 00:00:00 2001 From: Sam Ravnborg <sam@xxxxxxxxxxxx> Date: Fri, 4 Aug 2017 19:59:39 +0200 Subject: [PATCH] sparc64: update comments in U3memcpy Update comments about the range the different parts of the code copies, the original comments were wrong. Introduce a few descriptive labels too. No functional changes. Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx> --- No code fixes, so this is -next material. And this is anyway code that is seldomly touched. I had added the comments while trying to understand the bug where the return value was wrong. So let next reader benefits from these. Sam arch/sparc/lib/U3memcpy.S | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/arch/sparc/lib/U3memcpy.S b/arch/sparc/lib/U3memcpy.S index 54f98706b03b..df9fab8d99b6 100644 --- a/arch/sparc/lib/U3memcpy.S +++ b/arch/sparc/lib/U3memcpy.S @@ -168,18 +168,25 @@ ENDPROC(U3_retl_o2_and_7_plus_GS_plus_8) FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ srlx %o2, 31, %g2 cmp %g2, 0 + + /* software trap 5 "Range Check" if dst >= 0x80000000 */ tne %xcc, 5 PREAMBLE mov %o0, %o4 + + /* if len == 0 */ cmp %o2, 0 - be,pn %XCC, 85f + be,pn %XCC, end_return or %o0, %o1, %o3 + + /* if len < 16 */ cmp %o2, 16 - blu,a,pn %XCC, 80f + blu,a,pn %XCC, less_than_16 or %o3, %o2, %o3 + /* if len < 192 */ cmp %o2, (3 * 64) - blu,pt %XCC, 70f + blu,pt %XCC, less_than_192 andcc %o3, 0x7, %g0 /* Clobbers o5/g1/g2/g3/g7/icc/xcc. We must preserve @@ -362,7 +369,7 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ cmp %o2, 0 add %o1, %g1, %o1 VISExitHalf - be,pn %XCC, 85f + be,pn %XCC, end_return sub %o0, %o1, %o3 andcc %g1, 0x7, %g0 @@ -392,14 +399,15 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ sub %o2, 2, %o2 1: andcc %o2, 0x1, %g0 - be,pt %icc, 85f + be,pt %icc, end_return nop EX_LD(LOAD(ldub, %o1, %o5), U3_retl_o2) - ba,pt %xcc, 85f + ba,pt %xcc, end_return EX_ST(STORE(stb, %o5, %o1 + %o3), U3_retl_o2) .align 64 -70: /* 16 < len <= 64 */ + /* 16 <= len < 192 */ +less_than_192: bne,pn %XCC, 75f sub %o0, %o1, %o3 @@ -429,7 +437,7 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ EX_ST(STORE(stw, %o5, %o1 + %o3), U3_retl_o2_plus_4) add %o1, 0x4, %o1 1: cmp %o2, 0 - be,pt %XCC, 85f + be,pt %XCC, end_return nop ba,pt %xcc, 90f nop @@ -475,13 +483,14 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ srl %g1, 3, %g1 andcc %o2, 0x7, %o2 - be,pn %icc, 85f + be,pn %icc, end_return add %o1, %g1, %o1 ba,pt %xcc, 90f sub %o0, %o1, %o3 .align 64 -80: /* 0 < len <= 16 */ + /* 0 < len < 16 */ +less_than_16: andcc %o3, 0x3, %g0 bne,pn %XCC, 90f sub %o0, %o1, %o3 @@ -493,7 +502,8 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ bgu,pt %XCC, 1b add %o1, 4, %o1 -85: retl +end_return: + retl mov EX_RETVAL(%o4), %o0 .align 32 -- 2.12.0 -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
