[src/trunk]: src/sys/arch/sh3/sh3 Do not obfuscate r0 as "reg_tmp0".

[uwe <uwe%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f05fabde2688
branches:  trunk
changeset: 986302:f05fabde2688
user:      uwe <uwe%NetBSD.org@localhost>
date:      Sat Sep 18 15:09:05 2021 +0000

description:
Do not obfuscate r0 as "reg_tmp0".

Using r0 as a temp is a common choice.  Some instructions _must_ use
r0 as the destination (like mova or instructions with immediates).
ABI uses r0 as the return register.  So a helpful name is not that
helpful for the former use case (temp) and is confusing for the latter
two (ISA or ABI constraints).  Same object code is generated.

diffstat:

 sys/arch/sh3/sh3/cpu_in_cksum.S |  87 ++++++++++++++++++++--------------------
 1 files changed, 43 insertions(+), 44 deletions(-)

diffs (194 lines):

diff -r 56b06c0a90e2 -r f05fabde2688 sys/arch/sh3/sh3/cpu_in_cksum.S
--- a/sys/arch/sh3/sh3/cpu_in_cksum.S   Sat Sep 18 14:57:10 2021 +0000
+++ b/sys/arch/sh3/sh3/cpu_in_cksum.S   Sat Sep 18 15:09:05 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu_in_cksum.S,v 1.8 2021/09/18 14:57:10 uwe Exp $     */
+/*     $NetBSD: cpu_in_cksum.S,v 1.9 2021/09/18 15:09:05 uwe Exp $     */
 
 /*-
  * Copyright (c) 2000 SHIMIZU Ryo <ryo%misakimix.org@localhost>
@@ -34,10 +34,9 @@
 #include <machine/asm.h>
 #include "assym.h"
 
-__KERNEL_RCSID(0, "$NetBSD: cpu_in_cksum.S,v 1.8 2021/09/18 14:57:10 uwe Exp $")
+__KERNEL_RCSID(0, "$NetBSD: cpu_in_cksum.S,v 1.9 2021/09/18 15:09:05 uwe Exp $")
 
 
-#define        reg_tmp0                r0
 #define        reg_byte_swapped        r1
 #define        reg_mlen                r2
 #define        reg_tmp3                r3
@@ -49,39 +48,39 @@
 
 
 #define        REDUCE  \
-       swap.w  reg_sum, reg_tmp0       ; \
+       swap.w  reg_sum, r0             ; \
        extu.w  reg_sum, reg_sum        ; \
-       extu.w  reg_tmp0, reg_tmp0      ; \
-       add     reg_tmp0, reg_sum
+       extu.w  r0, r0                  ; \
+       add     r0, reg_sum
 
 #define        ROL     \
        shll8   reg_sum
 
 #if _BYTE_ORDER == BIG_ENDIAN
 #define        ADDB    \
-       mov.b   @reg_w+, reg_tmp0       ; \
+       mov.b   @reg_w+, r0             ; \
        ROL                             ; \
-       extu.b  reg_tmp0, reg_tmp0      ; \
-       add     reg_tmp0, reg_sum       ; \
+       extu.b  r0, r0  ; \
+       add     r0, reg_sum     ; \
        not     reg_byte_swapped, reg_byte_swapped
 #else
 #define        ADDB    \
-       mov.b   @reg_w+, reg_tmp0       ; \
-       extu.b  reg_tmp0, reg_tmp0      ; \
-       add     reg_tmp0, reg_sum       ; \
-       ROL                             ; \
+       mov.b   @reg_w+, r0     ; \
+       extu.b  r0, r0          ; \
+       add     r0, reg_sum     ; \
+       ROL                     ; \
        not     reg_byte_swapped, reg_byte_swapped
 #endif
 
 
 #define        ADDS    \
-       mov.w   @reg_w+, reg_tmp0       ; \
-       extu.w  reg_tmp0, reg_tmp0      ; \
-       add     reg_tmp0, reg_sum
+       mov.w   @reg_w+, r0     ; \
+       extu.w  r0, r0          ; \
+       add     r0, reg_sum
 
 #define        ADDCL   \
-       mov.l   @reg_w+, reg_tmp0       ; \
-       addc    reg_tmp0, reg_sum
+       mov.l   @reg_w+, r0     ; \
+       addc    r0, reg_sum
 
 #define        FORWARD1        \
        add     #-1, reg_mlen
@@ -149,38 +148,38 @@
        sub     reg_mlen, reg_len
 
 
-       mov     reg_w, reg_tmp0
-       tst     #1, reg_tmp0
+       mov     reg_w, r0
+       tst     #1, r0
        bt/s    1f
-       REDUCE          /* 1st instruction break only reg_tmp0(r0) */
+       REDUCE          /* 1st instruction break only r0 */
        ADDB
        FORWARD1
 1:
 
 
-       mov     #1, reg_tmp0
-       cmp/gt  reg_tmp0, reg_mlen
+       mov     #1, r0
+       cmp/gt  r0, reg_mlen
        bf/s    1f
-       mov     reg_w, reg_tmp0
-       tst     #2, reg_tmp0
+       mov     reg_w, r0
+       tst     #2, r0
        bt/s    1f
-       REDUCE          /* 1st instruction break only reg_tmp0(r0) */
+       REDUCE          /* 1st instruction break only r0 */
        ADDS
        FORWARD2
 1:
 
 
 
-       mov     #127, reg_tmp0
-       cmp/hi  reg_tmp0, reg_mlen
+       mov     #127, r0
+       cmp/hi  r0, reg_mlen
        bf      1f
 
 do_cksum128:
        bsr     cksum128
         nop
 
-       mov     #127, reg_tmp0
-       cmp/hi  reg_tmp0, reg_mlen
+       mov     #127, r0
+       cmp/hi  r0, reg_mlen
        bt      do_cksum128
 1:
 
@@ -190,8 +189,8 @@
 
        REDUCE
 
-       mov     #1, reg_tmp0
-       cmp/gt  reg_tmp0, reg_mlen
+       mov     #1, r0
+       cmp/gt  r0, reg_mlen
        bf      1f
        ADDS
        FORWARD2
@@ -214,7 +213,7 @@
 
        tst     reg_byte_swapped, reg_byte_swapped
        bt/s    1f
-       REDUCE          /* 1st instruction break only reg_tmp0(r0) */
+       REDUCE          /* 1st instruction break only r0(r0) */
        ROL
 1:
 
@@ -230,13 +229,13 @@
 
 
 out_of_mbufs:
-       mova    .L_message_out_of_data, reg_tmp0
+       mova    .L_message_out_of_data, r0
        mov.l   .L_printf, reg_tmp3
 
        mov.l   reg_sum, @-sp   /* save: call clobbered register */
 
 1:     CALL    reg_tmp3
-        mov    reg_tmp0, r4
+        mov    r0, r4
 
        bra     in_cksum_return
         mov.l  @sp+, reg_sum   /* restore */
@@ -256,14 +255,14 @@
 
        .align  2
 cksum128mod:
-       mov     reg_mlen, reg_tmp0
-       and     #124, reg_tmp0
-       sub     reg_tmp0, reg_mlen
-       mov     reg_tmp0, reg_tmp3
+       mov     reg_mlen, r0
+       and     #124, r0
+       sub     r0, reg_mlen
+       mov     r0, reg_tmp3
 
-       mova    cksum128_tail, reg_tmp0
-       sub     reg_tmp3, reg_tmp0
-       jmp     @reg_tmp0
+       mova    cksum128_tail, r0
+       sub     reg_tmp3, r0
+       jmp     @r0
         clrt
 
        .align  2
@@ -305,6 +304,6 @@
        ADDCL
        ADDCL
 cksum128_tail:
-       mov     #0, reg_tmp0
+       mov     #0, r0
        rts
-        addc   reg_tmp0, reg_sum
+        addc   r0, reg_sum