Re: sparc64: constify ddb instruction table

[Klemens Nanni]

On Fri, Oct 21, 2022 at 11:29:32AM -0900, Philip Guenther wrote:
> On Fri, Oct 21, 2022 at 11:04 AM Klemens Nanni <k...@openbsd.org> wrote:
> 
> > --- a/sys/arch/sparc64/sparc64/db_disasm.c
> > +++ b/sys/arch/sparc64/sparc64/db_disasm.c
> >
> ...
> 
> > @@ -877,7 +877,7 @@ struct sparc_insn sparc_i[] = {
> >  vaddr_t
> >  db_disasm(vaddr_t loc, int altfmt)
> >  {
> > -       struct sparc_insn*      i_ptr = (struct sparc_insn *)&sparc_i;
> > +       const struct sparc_insn *i_ptr = (const struct sparc_insn
> > *)&sparc_i;
> >
> 
> What's with that cast?  Is it only there because sparc_i is an array and
> it's wrong to take its address when we just want a pointer to its first
> element?  I mean, shouldn't that line just (with const) be:
>         const struct sparc_insn *i_ptr = sparc_i;    /* or &sparc_i[0] */

Sure, that also works.

diff --git a/sys/arch/sparc64/sparc64/db_disasm.c 
b/sys/arch/sparc64/sparc64/db_disasm.c
index b697ad5e163..7f7056f6753 100644
--- a/sys/arch/sparc64/sparc64/db_disasm.c
+++ b/sys/arch/sparc64/sparc64/db_disasm.c
@@ -153,7 +153,7 @@ char *prefetch[] = {
 /* The sparc instruction table has a format field which tells what
    the operand structure for this instruction is. Here are the codes:
 
-Modifiers (nust be first):
+Modifiers (must be first):
        a -- opcode has annul bit
        p -- opcode has branch prediction bit
 
@@ -201,7 +201,7 @@ V8 only:
 */
 
 
-struct sparc_insn sparc_i[] = {
+const struct sparc_insn sparc_i[] = {
 
        /*
         * Format 1: Call
@@ -217,7 +217,7 @@ struct sparc_insn sparc_i[] = {
        /* Note: if imm22 is zero then this is actually a "nop" grrr... */
        {(FORMAT2(0, 0x4)), "sethi", "Cd"},
 
-       /* Branch on Integer Co`ndition Codes "Bicc" */
+       /* Branch on Integer Condition Codes "Bicc" */
        {(FORMAT2(0, 2) | COND(8)), "ba", "a,m"},
        {(FORMAT2(0, 2) | COND(0)), "bn", "a,m"},
        {(FORMAT2(0, 2) | COND(9)), "bne", "a,m"},
@@ -877,7 +877,7 @@ struct sparc_insn sparc_i[] = {
 vaddr_t
 db_disasm(vaddr_t loc, int altfmt)
 {
-       struct sparc_insn*      i_ptr = (struct sparc_insn *)&sparc_i;
+       const struct sparc_insn *i_ptr = sparc_i;
 
        unsigned int insn, you_lose, bitmask;
        int matchp;