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RE: [Ping^2] [PATCH, ARM, libgcc] New aeabi_idiv function for armv6-m


Ping https://gcc.gnu.org/ml/gcc-patches/2014-12/msg01059.html.

> -----Original Message-----
> From: gcc-patches-owner@gcc.gnu.org [mailto:gcc-patches-
> owner@gcc.gnu.org] On Behalf Of Hale Wang
> Sent: Friday, December 12, 2014 9:36 AM
> To: gcc-patches
> Subject: RE: [Ping] [PATCH, ARM, libgcc] New aeabi_idiv function for armv6-
> m
> 
> Ping? Already applied to arm/embedded-4_9-branch, is it OK for trunk?
> 
> -Hale
> 
> > -----Original Message-----
> > From: Joey Ye [mailto:joey.ye.cc@gmail.com]
> > Sent: Thursday, November 27, 2014 10:01 AM
> > To: Hale Wang
> > Cc: gcc-patches
> > Subject: Re: [PATCH, ARM, libgcc] New aeabi_idiv function for armv6-m
> >
> > OK applying to arm/embedded-4_9-branch, though you still need
> > maintainer approval into trunk.
> >
> > - Joey
> >
> > On Wed, Nov 26, 2014 at 11:43 AM, Hale Wang <hale.wang@arm.com>
> wrote:
> > > Hi,
> > >
> > > This patch ports the aeabi_idiv routine from Linaro Cortex-Strings
> > > (https://git.linaro.org/toolchain/cortex-strings.git), which was
> > > contributed by ARM under Free BSD license.
> > >
> > > The new aeabi_idiv routine is used to replace the one in
> > > libgcc/config/arm/lib1funcs.S. This replacement happens within the
> > > Thumb1 wrapper. The new routine is under LGPLv3 license.
> > >
> > > The main advantage of this version is that it can improve the
> > > performance of the aeabi_idiv function for Thumb1. This solution
> > > will also increase the code size. So it will only be used if
> > > __OPTIMIZE_SIZE__ is
> > not defined.
> > >
> > > Make check passed for armv6-m.
> > >
> > > OK for trunk?
> > >
> > > Thanks,
> > > Hale Wang
> > >
> > > libgcc/ChangeLog:
> > >
> > > 2014-11-26  Hale Wang  <hale.wang@arm.com>
> > >
> > >         * config/arm/lib1funcs.S: Add new wrapper.
> > >
> > > ===============================================
> > > diff --git a/libgcc/config/arm/lib1funcs.S
> > > b/libgcc/config/arm/lib1funcs.S index b617137..de66c81 100644
> > > --- a/libgcc/config/arm/lib1funcs.S
> > > +++ b/libgcc/config/arm/lib1funcs.S
> > > @@ -306,34 +306,12 @@ LSYM(Lend_fde):
> > >  #ifdef __ARM_EABI__
> > >  .macro THUMB_LDIV0 name signed
> > >  #if defined(__ARM_ARCH_6M__)
> > > -       .ifc \signed, unsigned
> > > -       cmp     r0, #0
> > > -       beq     1f
> > > -       mov     r0, #0
> > > -       mvn     r0, r0          @ 0xffffffff
> > > -1:
> > > -       .else
> > > -       cmp     r0, #0
> > > -       beq     2f
> > > -       blt     3f
> > > +
> > > +       push    {r0, lr}
> > >         mov     r0, #0
> > > -       mvn     r0, r0
> > > -       lsr     r0, r0, #1      @ 0x7fffffff
> > > -       b       2f
> > > -3:     mov     r0, #0x80
> > > -       lsl     r0, r0, #24     @ 0x80000000
> > > -2:
> > > -       .endif
> > > -       push    {r0, r1, r2}
> > > -       ldr     r0, 4f
> > > -       adr     r1, 4f
> > > -       add     r0, r1
> > > -       str     r0, [sp, #8]
> > > -       @ We know we are not on armv4t, so pop pc is safe.
> > > -       pop     {r0, r1, pc}
> > > -       .align  2
> > > -4:
> > > -       .word   __aeabi_idiv0 - 4b
> > > +       bl      SYM(__aeabi_idiv0)
> > > +       pop     {r1, pc}
> > > +
> > >  #elif defined(__thumb2__)
> > >         .syntax unified
> > >         .ifc \signed, unsigned
> > > @@ -927,7 +905,158 @@ LSYM(Lover7):
> > >         add     dividend, work
> > >    .endif
> > >  LSYM(Lgot_result):
> > > -.endm
> > > +.endm
> > > +
> > > +#if defined(__prefer_thumb__)
> > && !defined(__OPTIMIZE_SIZE__) .macro
> > > +BranchToDiv n, label
> > > +       lsr     curbit, dividend, \n
> > > +       cmp     curbit, divisor
> > > +       blo     \label
> > > +.endm
> > > +
> > > +.macro DoDiv n
> > > +       lsr     curbit, dividend, \n
> > > +       cmp     curbit, divisor
> > > +       bcc     1f
> > > +       lsl     curbit, divisor, \n
> > > +       sub     dividend, dividend, curbit
> > > +
> > > +1:     adc     result, result
> > > +.endm
> > > +
> > > +.macro THUMB1_Div_Positive
> > > +       mov     result, #0
> > > +       BranchToDiv #1, LSYM(Lthumb1_div1)
> > > +       BranchToDiv #4, LSYM(Lthumb1_div4)
> > > +       BranchToDiv #8, LSYM(Lthumb1_div8)
> > > +       BranchToDiv #12, LSYM(Lthumb1_div12)
> > > +       BranchToDiv #16, LSYM(Lthumb1_div16)
> > > +LSYM(Lthumb1_div_large_positive):
> > > +       mov     result, #0xff
> > > +       lsl     divisor, divisor, #8
> > > +       rev     result, result
> > > +       lsr     curbit, dividend, #16
> > > +       cmp     curbit, divisor
> > > +       blo     1f
> > > +       asr     result, #8
> > > +       lsl     divisor, divisor, #8
> > > +       beq     LSYM(Ldivbyzero_waypoint)
> > > +
> > > +1:     lsr     curbit, dividend, #12
> > > +       cmp     curbit, divisor
> > > +       blo     LSYM(Lthumb1_div12)
> > > +       b       LSYM(Lthumb1_div16)
> > > +LSYM(Lthumb1_div_loop):
> > > +       lsr     divisor, divisor, #8
> > > +LSYM(Lthumb1_div16):
> > > +       Dodiv   #15
> > > +       Dodiv   #14
> > > +       Dodiv   #13
> > > +       Dodiv   #12
> > > +LSYM(Lthumb1_div12):
> > > +       Dodiv   #11
> > > +       Dodiv   #10
> > > +       Dodiv   #9
> > > +       Dodiv   #8
> > > +       bcs     LSYM(Lthumb1_div_loop)
> > > +LSYM(Lthumb1_div8):
> > > +       Dodiv   #7
> > > +       Dodiv   #6
> > > +       Dodiv   #5
> > > +LSYM(Lthumb1_div5):
> > > +       Dodiv   #4
> > > +LSYM(Lthumb1_div4):
> > > +       Dodiv   #3
> > > +LSYM(Lthumb1_div3):
> > > +       Dodiv   #2
> > > +LSYM(Lthumb1_div2):
> > > +       Dodiv   #1
> > > +LSYM(Lthumb1_div1):
> > > +       sub     divisor, dividend, divisor
> > > +       bcs     1f
> > > +       cpy     divisor, dividend
> > > +
> > > +1:     adc     result, result
> > > +       cpy     dividend, result
> > > +       RET
> > > +
> > > +LSYM(Ldivbyzero_waypoint):
> > > +       b       LSYM(Ldiv0)
> > > +.endm
> > > +
> > > +.macro THUMB1_Div_Negative
> > > +       lsr     result, divisor, #31
> > > +       beq     1f
> > > +       neg     divisor, divisor
> > > +
> > > +1:     asr     curbit, dividend, #32
> > > +       bcc     2f
> > > +       neg     dividend, dividend
> > > +
> > > +2:     eor     curbit, result
> > > +       mov     result, #0
> > > +       cpy     ip, curbit
> > > +       BranchToDiv #4, LSYM(Lthumb1_div_negative4)
> > > +       BranchToDiv #8, LSYM(Lthumb1_div_negative8)
> > > +LSYM(Lthumb1_div_large):
> > > +       mov     result, #0xfc
> > > +       lsl     divisor, divisor, #6
> > > +       rev     result, result
> > > +       lsr     curbit, dividend, #8
> > > +       cmp     curbit, divisor
> > > +       blo     LSYM(Lthumb1_div_negative8)
> > > +
> > > +       lsl     divisor, divisor, #6
> > > +       asr     result, result, #6
> > > +       cmp     curbit, divisor
> > > +       blo     LSYM(Lthumb1_div_negative8)
> > > +
> > > +       lsl     divisor, divisor, #6
> > > +       asr     result, result, #6
> > > +       cmp     curbit, divisor
> > > +       blo     LSYM(Lthumb1_div_negative8)
> > > +
> > > +       lsl     divisor, divisor, #6
> > > +       beq     LSYM(Ldivbyzero_negative)
> > > +       asr     result, result, #6
> > > +       b       LSYM(Lthumb1_div_negative8)
> > > +LSYM(Lthumb1_div_negative_loop):
> > > +       lsr     divisor, divisor, #6
> > > +LSYM(Lthumb1_div_negative8):
> > > +       DoDiv   #7
> > > +       DoDiv   #6
> > > +       DoDiv   #5
> > > +       DoDiv   #4
> > > +LSYM(Lthumb1_div_negative4):
> > > +       DoDiv   #3
> > > +       DoDiv   #2
> > > +       bcs     LSYM(Lthumb1_div_negative_loop)
> > > +       DoDiv   #1
> > > +       sub     divisor, dividend, divisor
> > > +       bcs     1f
> > > +       cpy     divisor, dividend
> > > +
> > > +1:     cpy     curbit, ip
> > > +       adc     result, result
> > > +       asr     curbit, curbit, #1
> > > +       cpy     dividend, result
> > > +       bcc     2f
> > > +       neg     dividend, dividend
> > > +       cmp     curbit, #0
> > > +
> > > +2:     bpl     3f
> > > +       neg     divisor, divisor
> > > +
> > > +3:     RET
> > > +
> > > +LSYM(Ldivbyzero_negative):
> > > +       cpy     curbit, ip
> > > +       asr     curbit, curbit, #1
> > > +       bcc     LSYM(Ldiv0)
> > > +       neg     dividend, dividend
> > > +.endm
> > > +#endif /* ARM Thumb version.  */
> > > +
> > >  /*
> > > --------------------------------------------------------------------
> > > --
> > > --
> > > */
> > >  /*             Start of the Real Functions
> > > */
> > >  /*
> > > --------------------------------------------------------------------
> > > --
> > > --
> > > */
> > > @@ -937,6 +1066,7 @@ LSYM(Lgot_result):
> > >
> > >         FUNC_START udivsi3
> > >         FUNC_ALIAS aeabi_uidiv udivsi3
> > > +#if defined(__OPTIMIZE_SIZE__)
> > >
> > >         cmp     divisor, #0
> > >         beq     LSYM(Ldiv0)
> > > @@ -954,6 +1084,13 @@ LSYM(udivsi3_skip_div0_test):
> > >         pop     { work }
> > >         RET
> > >
> > > +#else
> > > +
> > > +LSYM(udivsi3_skip_div0_test):
> > > +       THUMB1_Div_Positive
> > > +
> > > +#endif
> > > +
> > >  #elif defined(__ARM_ARCH_EXT_IDIV__)
> > >
> > >         ARM_FUNC_START udivsi3
> > > @@ -1066,7 +1203,7 @@ LSYM(Lover10):
> > >         RET
> > >
> > >  #else  /* ARM version.  */
> > > -
> > > +
> > >         FUNC_START umodsi3
> > >
> > >         subs    r2, r1, #1                      @ compare divisor with 1
> > > @@ -1091,8 +1228,9 @@ LSYM(Lover10):
> > >
> > >  #if defined(__prefer_thumb__)
> > >
> > > -       FUNC_START divsi3
> > > +       FUNC_START divsi3
> > >         FUNC_ALIAS aeabi_idiv divsi3
> > > +#if defined(__OPTIMIZE_SIZE__)
> > >
> > >         cmp     divisor, #0
> > >         beq     LSYM(Ldiv0)
> > > @@ -1115,7 +1253,7 @@ LSYM(Lover11):
> > >         blo     LSYM(Lgot_result)
> > >
> > >         THUMB_DIV_MOD_BODY 0
> > > -
> > > +
> > >         mov     r0, result
> > >         mov     work, ip
> > >         cmp     work, #0
> > > @@ -1124,6 +1262,20 @@ LSYM(Lover11):
> > >  LSYM(Lover12):
> > >         pop     { work }
> > >         RET
> > > +#else
> > > +
> > > +LSYM(divsi3_skip_div0_test):
> > > +       cpy     curbit, dividend
> > > +       orr     curbit, divisor
> > > +       bmi     LSYM(Lthumb1_div_negative)
> > > +
> > > +LSYM(Lthumb1_div_positive):
> > > +       THUMB1_Div_Positive
> > > +
> > > +LSYM(Lthumb1_div_negative):
> > > +       THUMB1_Div_Negative
> > > +
> > > +#endif /* __OPTIMIZE_SIZE__ */
> > >
> > >  #elif defined(__ARM_ARCH_EXT_IDIV__)
> > >
> > > @@ -1136,8 +1288,8 @@ LSYM(Lover12):
> > >         RET
> > >
> > >  #else /* ARM/Thumb-2 version.  */
> > > -
> > > -       ARM_FUNC_START divsi3
> > > +
> > > +       ARM_FUNC_START divsi3
> > >         ARM_FUNC_ALIAS aeabi_idiv divsi3
> > >
> > >         cmp     r1, #0
> > > ===============================================
> 
> 
> 
> 





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