Re: [9front] Patch: Assemblers do not handle minimum vlong value correctly.

[Benjamin Purcell <benjapurcell@gmail.com>]

Thank you, committed.

-spew

On Tue, Mar 21, 2017 at 11:48 PM, Ori Bernstein <ori@eigenstate.org> wrote:
> The Plan 9 assemblers use strtoll to parse the integer literals
> in their input. It turns out that this is almost correct, but
> VLONG_MIN is clamped. This patch changes to use strtoull
> in order to allow the full range of integers.
>
> Below is a program that demosntrates the problem:
>
>         term% cat test.s
>         GLOBL L2<>+0(SB),$8
>                 DATA L2<>+0(SB)/8,$-9223372036854775808
>
>         TEXT main+0(SB),2,$0
>                 MOVQ L2<>+0(SB),AX
>                 RET
>
>         term% 6a test.s
>         term% 6l test.6 /amd64/lib/libc.a
>         term% acid 6.out
>         6.out:amd64 plan 9 executable
>         /sys/lib/acid/port
>         /sys/lib/acid/amd64
>         acid: new()
>         33489: overflow _main   SUBQ    $0x90,SP
>         33489: breakpoint       main+0x8        RET
>         acid: *L2
>         0x8000000000000001
>         acid: -9223372036854775808
>         0x8000000000000000
>
> And the patch:
>
>
>         diff -r a01d0802d023 sys/src/cmd/cc/lexbody
>         --- a/sys/src/cmd/cc/lexbody    Mon Mar 20 19:15:40 2017 +0100
>         +++ b/sys/src/cmd/cc/lexbody    Tue Mar 21 21:45:44 2017 -0700
>         @@ -343,10 +343,9 @@
>                                 goto casee;
>                         *cp = 0;
>                         if(sizeof(yylval.lval) == sizeof(vlong))
>         -                       yylval.lval = strtoll(symb, nil, 10);
>         +                       yylval.lval = strtoull(symb, nil, 10);
>                         else
>         -                       yylval.lval = strtol(symb, nil, 10);
>         -
>         +                       yylval.lval = strtoul(symb, nil, 10);
>                 ncu:
>                         while(c == 'U' || c == 'u' || c == 'l' || c == 'L')
>                                 c = GETC();
>
> --
>     Ori Bernstein