On 1 May 2014 16:41, Richard Earnshaw <rearn...@arm.com> wrote:
> I think really, you've got three independent changes here:
Version 2 of this patch series is now a 9 patch series which addresses
most of the following. Exceptions discussed below.
> 1) Optimize the prologue/epilogue sequences when ldrd is available.
> 2) Replace the call to __gnu_ldivmod_helper with __udivmoddi4
I assume you mean __gnu_uldivmod_helper here, as __gnu_ldivmod_helper
performs signed division and can't be directly replaced with the
unsigned division performed by __udivmoddi4.
> 3) Optimize the code to __aeabi_ldivmod.
Converting to call __udivmoddi4, fixing up signedness of operands and
results and optimisation are all one change.
> Ideally, therefore, this is a three patch series, but it's then missing
> a few bits.
>
> 4) Step 2 can also be trivially applied to bpabi-v6m.S as well, since
> it's a direct swap of one function for another (unless I've misread the
> changes, I think the ABI of the two helper functions are the same).
For __aeabi_uldivmod this is true. For __aeabi_ldivmod this is not
trivial as the signedness fix-ups must be written.
> 5) Step 4 then makes __gnu_ldivmod_helper in bpabi.c a dead function
> which can be deleted. This is good because currently pulling in either
> 64-bit division function causes both these helper functions to be pulled
> in and thus the whole of the 64-bit div-mod code for both signed and
> unsigned values. That's particularly unfortunate for ARMv6m class
> devices as that's potentially a lot of redundant code.
Similarly, __gnu_uldivmod_helper not __gnu_ldivmod_helper.
I've included two patches which do the trivial steps for the unsigned case.
>
> Finally, I know this was the original code, but the complete lack of
> comments in this code made reviewing even the trivial parts a complete
> nightmare -- it took me half an hour before I remembered that
> __udivmoddi4 took three parameters, the third of which was on the stack:
> thus the messing around with sp/ip in the prologue wasn't just trivial
> padding but a necessary part of the function. Please could you add, at
> least some short comments clarifying the register disposition on input
> and what that prologue code is up to...
Done.
> Finally, how was this code tested?
It has been built and "make check" has been run with no regressions on:
arm-unknown-linux-gnueabihf --with-mode=thumb --with-arch=armv7-a
arm-unknown-linux-gnueabihf --with-mode=arm --with-arch=armv7-a
arm-unknown-linux-gnueabi --with-mode=arm --with-arch=armv5te
arm-unknown-linux-gnueabi --with-mode=arm --with-arch=armv4t
I have also run a simple test harness which checks the result of
several 64 bit division operations where gcc has been built with the
above configurations.
I am not currently set up with a way to test v6M, so those parts aren't tested.
> Anyway, some additional comments below:
>
> Don't repeat the function name for multiple tweaks to the same function;
> as mentioned above, if these are really separate changes they should be
> in separate submissions. Mixing unrelated changes just makes the
> reviewing step that much harder.
Done.
>> + strd ip,lr, [sp, #-16]!
>
> Space after comma.
Done
> Also, since you've essentially rewritten the entire function, can you
> please also reformat them to follow the coding style of the rest of the
> file: namely "<tab>OP<tab>operands".
Done
>> #else
>> + sub sp, sp, #8
>> do_push {sp, lr}
>> #endif
>
> Please add a comment that the value at *sp is the address of the the
> slot for the remainder.
Done
>> +#if defined(__thumb2__) && CAN_USE_LDRD
>> + sub ip, sp, #8
>> + strd ip,lr, [sp, #-16]!
>
> Space after comma.
Done
>> #else
>> + sub sp, sp, #8
>> do_push {sp, lr}
>> #endif
>> + cmp xxh, #0
>> + blt 1f
>> + cmp yyh, #0
>> + blt 2f
>> +
>> +98: cfi_push 98b - __aeabi_ldivmod, 0xe, -0xc, 0x10
>
> The CFI push should really precede your conditional tests, it relates to
> the do_push expression.
Done.
>> + bl SYM(__udivmoddi4) __PLT__
>> + ldr lr, [sp, #4]
>> +#if CAN_USE_LDRD
>> + ldrd r2, r3, [sp, #8]
>> + add sp, sp, #16
>> +#else
>> + add sp, sp, #8
>> + do_pop {r2, r3}
>> +#endif
>
> You're missing a CFI pop, which is needed when the values on the stack
> go out of scope.
The existing code doesn't do this. Since there are multiple exit
points from the optimised function the existing cfi_* macros aren't
sufficient (there is no cfi_save_state/cfi_restore_state), so I have
included a patch which uses the gas .cfi_* directives. This may be
interesting on non-DWARF or non-ELF platforms, if any are still
supported .
>> + RET
>> +1: /* xxh:xxl is negative */
>> + rsbs xxl, xxl, #0
>
> We're using unified syntax, so NEGS is preferable.
Done
>> + sbc xxh, xxh, xxh, lsl #1
>
> Worthy of a comment, Thumb2 has no RSC instruction, so use X - 2X.
Done
>> + cmp yyh, #0
>> + blt 3f
>> +98: cfi_push 98b - __aeabi_ldivmod, 0xe, -0xc, 0x10
>
> This CFI push looks wrong. You've already pushed things earlier. On
> the other hand, you should save the state before the CFI pop above, so
> that you can restore the state again for the next (ie this) block of code.
Done (see above)
>> +98: cfi_push 98b - __aeabi_ldivmod, 0xe, -0xc, 0x10
>> + bl SYM(__udivmoddi4) __PLT__
>> + ldr lr, [sp, #4]
>> +#if CAN_USE_LDRD
>> + ldrd r2, r3, [sp, #8]
>> + add sp, sp, #16
>> +#else
>> + add sp, sp, #8
>> + do_pop {r2, r3}
>> +#endif
>> + rsbs yyl, yyl, #0
>> + sbc yyh, yyh, yyh, lsl #1
>> + RET
>>
>> #endif /* L_aeabi_ldivmod */
>>
>
> You use the LDRD vs do_pop sequence identically several times. To avoid
> a lot of ifdefs, it might be worth considering a macro for this idiom to
> reduce the overall amount of conditionalized code.
Done.
The updated patch series is attached. Hopefully, patches 1 through 6
are now ready. Patches 7 through 9 can be dropped if necessary.
0001-Whitespace.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod): Fix whitespace.
(__aeabi_ldivmod): Fix whitespace.
0002-Add-comments.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod, __aeabi_ldivmod): Add comment
describing register usage on function entry and exit.
0003-Optimise-__aeabi_uldivmod-stack-manipulation.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod): Optimise stack pointer
manipulation.
0004-Optimise-__aeabi_uldivmod.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod): Perform division using call
to __udivmoddi4.
0005-Optimise-__aeabi_ldivmod-stack-manipulation.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_ldivmod): Optimise stack manipulation.
0006-Optimise-__aeabi_ldivmod.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_ldivmod): Perform division using
__udivmoddi4, and fixups for negative operands.
0007-Fix-cfi-annotations.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_ldivmod, __aeabi_uldivmod,
push_for_divide, pop_for_divide): Use .cfi_* directives for DWARF
annotations. Fix DWARF information.
0008-Use-__udivmoddi4-for-v6M-aeabi_uldivmod.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi-v6m.S (__aeabi_uldivmod): Perform division using
__udivmoddi4.
0009-Remove-__gnu_uldivmod_helper.patch
2014-05-22 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.c (__gnu_uldivmod_helper): Remove.
From d1453a43717939baf4f96a2c1ddb8b775f592c91 Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Mon, 12 May 2014 17:39:18 +0100
Subject: [PATCH 1/9] Whitespace
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod): Fix whitespace.
(__aeabi_ldivmod): Fix whitespace.
---
libgcc/config/arm/bpabi.S | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index 7772301..f47d715 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -124,20 +124,20 @@ ARM_FUNC_START aeabi_ulcmp
ARM_FUNC_START aeabi_ldivmod
cfi_start __aeabi_ldivmod, LSYM(Lend_aeabi_ldivmod)
- test_div_by_zero signed
+ test_div_by_zero signed
- sub sp, sp, #8
+ sub sp, sp, #8
#if defined(__thumb2__)
- mov ip, sp
- push {ip, lr}
+ mov ip, sp
+ push {ip, lr}
#else
- do_push {sp, lr}
+ do_push {sp, lr}
#endif
98: cfi_push 98b - __aeabi_ldivmod, 0xe, -0xc, 0x10
- bl SYM(__gnu_ldivmod_helper) __PLT__
- ldr lr, [sp, #4]
- add sp, sp, #8
- do_pop {r2, r3}
+ bl SYM(__gnu_ldivmod_helper) __PLT__
+ ldr lr, [sp, #4]
+ add sp, sp, #8
+ do_pop {r2, r3}
RET
cfi_end LSYM(Lend_aeabi_ldivmod)
@@ -147,20 +147,20 @@ ARM_FUNC_START aeabi_ldivmod
ARM_FUNC_START aeabi_uldivmod
cfi_start __aeabi_uldivmod, LSYM(Lend_aeabi_uldivmod)
- test_div_by_zero unsigned
+ test_div_by_zero unsigned
- sub sp, sp, #8
+ sub sp, sp, #8
#if defined(__thumb2__)
- mov ip, sp
- push {ip, lr}
+ mov ip, sp
+ push {ip, lr}
#else
- do_push {sp, lr}
+ do_push {sp, lr}
#endif
98: cfi_push 98b - __aeabi_uldivmod, 0xe, -0xc, 0x10
- bl SYM(__gnu_uldivmod_helper) __PLT__
- ldr lr, [sp, #4]
- add sp, sp, #8
- do_pop {r2, r3}
+ bl SYM(__gnu_uldivmod_helper) __PLT__
+ ldr lr, [sp, #4]
+ add sp, sp, #8
+ do_pop {r2, r3}
RET
cfi_end LSYM(Lend_aeabi_uldivmod)
--
1.9.1
From 8d420bee9b818cd51d836aab25be7e92f11afe15 Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Tue, 13 May 2014 13:10:58 +0100
Subject: [PATCH 2/9] Add comments
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod, __aeabi_ldivmod): Add comment
describing register usage on function entry and exit.
---
libgcc/config/arm/bpabi.S | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index f47d715..ae76cd3 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -122,6 +122,14 @@ ARM_FUNC_START aeabi_ulcmp
#ifdef L_aeabi_ldivmod
+/* Perform 64 bit signed division.
+ Inputs:
+ r0:r1 numerator
+ r2:r3 denominator
+ Outputs:
+ r0:r1 quotient
+ r2:r3 remainder
+ */
ARM_FUNC_START aeabi_ldivmod
cfi_start __aeabi_ldivmod, LSYM(Lend_aeabi_ldivmod)
test_div_by_zero signed
@@ -145,6 +153,14 @@ ARM_FUNC_START aeabi_ldivmod
#ifdef L_aeabi_uldivmod
+/* Perform 64 bit signed division.
+ Inputs:
+ r0:r1 numerator
+ r2:r3 denominator
+ Outputs:
+ r0:r1 quotient
+ r2:r3 remainder
+ */
ARM_FUNC_START aeabi_uldivmod
cfi_start __aeabi_uldivmod, LSYM(Lend_aeabi_uldivmod)
test_div_by_zero unsigned
--
1.9.1
From 8e996cd947311966665c13d46b4ee75c145d31f5 Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Mon, 12 May 2014 17:40:36 +0100
Subject: [PATCH 3/9] Optimise __aeabi_uldivmod (stack manipulation)
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod): Optimise stack pointer
manipulation.
---
libgcc/config/arm/bpabi.S | 54 +++++++++++++++++++++++++++++++++++++----------
1 file changed, 43 insertions(+), 11 deletions(-)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index ae76cd3..67246b0 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -120,6 +120,46 @@ ARM_FUNC_START aeabi_ulcmp
#endif
.endm
+/* we can use STRD/LDRD on v5TE and later, and any Thumb-2 architecture. */
+#if (defined(__ARM_EABI__) \
+ && (defined(__thumb2__) \
+ || (__ARM_ARCH >= 5 && defined(__TARGET_FEATURE_DSP))))
+#define CAN_USE_LDRD 1
+#else
+#define CAN_USE_LDRD 0
+#endif
+
+/* set up stack from for call to __udivmoddi4. At the end of the macro the
+ stack is arranged as follows:
+ sp+12 / space for remainder
+ sp+8 \ (written by __udivmoddi4)
+ sp+4 lr
+ sp+0 sp+8 [rp (remainder pointer) argument for __udivmoddi4]
+
+ */
+.macro push_for_divide fname
+#if defined(__thumb2__) && CAN_USE_LDRD
+ sub ip, sp, #8
+ strd ip, lr, [sp, #-16]!
+#else
+ sub sp, sp, #8
+ do_push {sp, lr}
+#endif
+98: cfi_push 98b - \fname, 0xe, -0xc, 0x10
+.endm
+
+/* restore stack */
+.macro pop_for_divide
+ ldr lr, [sp, #4]
+#if CAN_USE_LDRD
+ ldrd r2, r3, [sp, #8]
+ add sp, sp, #16
+#else
+ add sp, sp, #8
+ do_pop {r2, r3}
+#endif
+.endm
+
#ifdef L_aeabi_ldivmod
/* Perform 64 bit signed division.
@@ -165,18 +205,10 @@ ARM_FUNC_START aeabi_uldivmod
cfi_start __aeabi_uldivmod, LSYM(Lend_aeabi_uldivmod)
test_div_by_zero unsigned
- sub sp, sp, #8
-#if defined(__thumb2__)
- mov ip, sp
- push {ip, lr}
-#else
- do_push {sp, lr}
-#endif
-98: cfi_push 98b - __aeabi_uldivmod, 0xe, -0xc, 0x10
+ push_for_divide __aeabi_uldivmod
+ /* arguments in (r0:r1), (r2:r3) and *sp */
bl SYM(__gnu_uldivmod_helper) __PLT__
- ldr lr, [sp, #4]
- add sp, sp, #8
- do_pop {r2, r3}
+ pop_for_divide
RET
cfi_end LSYM(Lend_aeabi_uldivmod)
--
1.9.1
From 06da1a0fb2ccc21d41bc83cfcd4db99fca45dd44 Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Wed, 14 May 2014 14:15:58 +0100
Subject: [PATCH 4/9] Optimise __aeabi_uldivmod
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_uldivmod): Perform division using call
to __udivmoddi4.
---
libgcc/config/arm/bpabi.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index 67246b0..927e37f 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -207,7 +207,7 @@ ARM_FUNC_START aeabi_uldivmod
push_for_divide __aeabi_uldivmod
/* arguments in (r0:r1), (r2:r3) and *sp */
- bl SYM(__gnu_uldivmod_helper) __PLT__
+ bl SYM(__udivmoddi4) __PLT__
pop_for_divide
RET
cfi_end LSYM(Lend_aeabi_uldivmod)
--
1.9.1
From 6cfc99a2d765346b77c3d6d8c29e958d877e400c Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Mon, 12 May 2014 17:41:44 +0100
Subject: [PATCH 5/9] Optimise __aeabi_ldivmod (stack manipulation)
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_ldivmod): Optimise stack manipulation.
---
libgcc/config/arm/bpabi.S | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index 927e37f..3f9ece5 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -174,18 +174,10 @@ ARM_FUNC_START aeabi_ldivmod
cfi_start __aeabi_ldivmod, LSYM(Lend_aeabi_ldivmod)
test_div_by_zero signed
- sub sp, sp, #8
-#if defined(__thumb2__)
- mov ip, sp
- push {ip, lr}
-#else
- do_push {sp, lr}
-#endif
-98: cfi_push 98b - __aeabi_ldivmod, 0xe, -0xc, 0x10
+ push_for_divide __aeabi_ldivmod
+ /* arguments in (r0:r1), (r2:r3) and *sp */
bl SYM(__gnu_ldivmod_helper) __PLT__
- ldr lr, [sp, #4]
- add sp, sp, #8
- do_pop {r2, r3}
+ pop_for_divide
RET
cfi_end LSYM(Lend_aeabi_ldivmod)
--
1.9.1
From 6987775f7523248144c84d036cbdc3ae0ba6b5da Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Wed, 14 May 2014 14:17:30 +0100
Subject: [PATCH 6/9] Optimise __aeabi_ldivmod
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_ldivmod): Perform division using
__udivmoddi4, and fixups for negative operands.
---
libgcc/config/arm/bpabi.S | 41 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index 3f9ece5..c044167 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -175,10 +175,49 @@ ARM_FUNC_START aeabi_ldivmod
test_div_by_zero signed
push_for_divide __aeabi_ldivmod
+ cmp xxh, #0
+ blt 1f
+ cmp yyh, #0
+ blt 2f
+ /* arguments in (r0:r1), (r2:r3) and *sp */
+ bl SYM(__udivmoddi4) __PLT__
+ pop_for_divide
+ RET
+
+1: /* xxh:xxl is negative */
+ negs xxl, xxl
+ sbc xxh, xxh, xxh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
+ cmp yyh, #0
+ blt 3f
+ /* arguments in (r0:r1), (r2:r3) and *sp */
+ bl SYM(__udivmoddi4) __PLT__
+ pop_for_divide
+ negs xxl, xxl
+ sbc xxh, xxh, xxh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
+ negs yyl, yyl
+ sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
+ RET
+
+2: /* only yyh:yyl is negative */
+ negs yyl, yyl
+ sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
+ /* arguments in (r0:r1), (r2:r3) and *sp */
+ bl SYM(__udivmoddi4) __PLT__
+ pop_for_divide
+ negs xxl, xxl
+ sbc xxh, xxh, xxh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
+ RET
+
+3: /* both xxh:xxl and yyh:yyl are negative */
+ negs yyl, yyl
+ sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
/* arguments in (r0:r1), (r2:r3) and *sp */
- bl SYM(__gnu_ldivmod_helper) __PLT__
+ bl SYM(__udivmoddi4) __PLT__
pop_for_divide
+ negs yyl, yyl
+ sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
RET
+
cfi_end LSYM(Lend_aeabi_ldivmod)
#endif /* L_aeabi_ldivmod */
--
1.9.1
From d2be16c4cb112fe32100f4c4c250fa5acd72c777 Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Wed, 14 May 2014 15:42:19 +0100
Subject: [PATCH 7/9] Fix cfi annotations
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.S (__aeabi_ldivmod, __aeabi_uldivmod,
push_for_divide, pop_for_divide): Use .cfi_* directives for DWARF
annotations. Fix DWARF information.
---
libgcc/config/arm/bpabi.S | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/libgcc/config/arm/bpabi.S b/libgcc/config/arm/bpabi.S
index c044167..959ecb1 100644
--- a/libgcc/config/arm/bpabi.S
+++ b/libgcc/config/arm/bpabi.S
@@ -22,6 +22,8 @@
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
+ .cfi_sections .debug_frame
+
#ifdef __ARM_EABI__
/* Some attributes that are common to all routines in this file. */
/* Tag_ABI_align_needed: This code does not require 8-byte
@@ -145,7 +147,8 @@ ARM_FUNC_START aeabi_ulcmp
sub sp, sp, #8
do_push {sp, lr}
#endif
-98: cfi_push 98b - \fname, 0xe, -0xc, 0x10
+ .cfi_adjust_cfa_offset 16
+ .cfi_offset 14, -12
.endm
/* restore stack */
@@ -158,6 +161,8 @@ ARM_FUNC_START aeabi_ulcmp
add sp, sp, #8
do_pop {r2, r3}
#endif
+ .cfi_restore 14
+ .cfi_adjust_cfa_offset 0
.endm
#ifdef L_aeabi_ldivmod
@@ -171,7 +176,7 @@ ARM_FUNC_START aeabi_ulcmp
r2:r3 remainder
*/
ARM_FUNC_START aeabi_ldivmod
- cfi_start __aeabi_ldivmod, LSYM(Lend_aeabi_ldivmod)
+ .cfi_startproc
test_div_by_zero signed
push_for_divide __aeabi_ldivmod
@@ -181,16 +186,19 @@ ARM_FUNC_START aeabi_ldivmod
blt 2f
/* arguments in (r0:r1), (r2:r3) and *sp */
bl SYM(__udivmoddi4) __PLT__
+ .cfi_remember_state
pop_for_divide
RET
1: /* xxh:xxl is negative */
+ .cfi_restore_state
negs xxl, xxl
sbc xxh, xxh, xxh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
cmp yyh, #0
blt 3f
/* arguments in (r0:r1), (r2:r3) and *sp */
bl SYM(__udivmoddi4) __PLT__
+ .cfi_remember_state
pop_for_divide
negs xxl, xxl
sbc xxh, xxh, xxh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
@@ -199,16 +207,19 @@ ARM_FUNC_START aeabi_ldivmod
RET
2: /* only yyh:yyl is negative */
+ .cfi_restore_state
negs yyl, yyl
sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
/* arguments in (r0:r1), (r2:r3) and *sp */
bl SYM(__udivmoddi4) __PLT__
+ .cfi_remember_state
pop_for_divide
negs xxl, xxl
sbc xxh, xxh, xxh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
RET
3: /* both xxh:xxl and yyh:yyl are negative */
+ .cfi_restore_state
negs yyl, yyl
sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
/* arguments in (r0:r1), (r2:r3) and *sp */
@@ -218,7 +229,7 @@ ARM_FUNC_START aeabi_ldivmod
sbc yyh, yyh, yyh, lsl #1 /* Thumb-2 has no RSC, so use X - 2X */
RET
- cfi_end LSYM(Lend_aeabi_ldivmod)
+ .cfi_endproc
#endif /* L_aeabi_ldivmod */
@@ -233,7 +244,7 @@ ARM_FUNC_START aeabi_ldivmod
r2:r3 remainder
*/
ARM_FUNC_START aeabi_uldivmod
- cfi_start __aeabi_uldivmod, LSYM(Lend_aeabi_uldivmod)
+ .cfi_startproc
test_div_by_zero unsigned
push_for_divide __aeabi_uldivmod
@@ -241,7 +252,7 @@ ARM_FUNC_START aeabi_uldivmod
bl SYM(__udivmoddi4) __PLT__
pop_for_divide
RET
- cfi_end LSYM(Lend_aeabi_uldivmod)
+ .cfi_endproc
#endif /* L_aeabi_divmod */
--
1.9.1
From 314caabcda45861371cfed73b29cf77c652da018 Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Mon, 12 May 2014 18:51:54 +0100
Subject: [PATCH 8/9] Use __udivmoddi4 for v6M aeabi_uldivmod
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi-v6m.S (__aeabi_uldivmod): Perform division using
__udivmoddi4.
---
libgcc/config/arm/bpabi-v6m.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libgcc/config/arm/bpabi-v6m.S b/libgcc/config/arm/bpabi-v6m.S
index 0bf2e55..d549fa6 100644
--- a/libgcc/config/arm/bpabi-v6m.S
+++ b/libgcc/config/arm/bpabi-v6m.S
@@ -148,7 +148,7 @@ FUNC_START aeabi_uldivmod
mov r0, sp
push {r0, lr}
ldr r0, [sp, #8]
- bl SYM(__gnu_uldivmod_helper)
+ bl SYM(__udivmoddi4)
ldr r3, [sp, #4]
mov lr, r3
add sp, sp, #8
--
1.9.1
From 540a4016a32953cb37dbe2f7ea1ec3e1cf0bfdcf Mon Sep 17 00:00:00 2001
From: Charles Baylis <charles.bay...@linaro.org>
Date: Mon, 12 May 2014 18:58:04 +0100
Subject: [PATCH 9/9] Remove __gnu_uldivmod_helper
2014-05-12 Charles Baylis <charles.bay...@linaro.org>
* config/arm/bpabi.c (__gnu_uldivmod_helper): Remove.
---
libgcc/config/arm/bpabi.c | 14 --------------
1 file changed, 14 deletions(-)
diff --git a/libgcc/config/arm/bpabi.c b/libgcc/config/arm/bpabi.c
index 7b155cc..e90d044 100644
--- a/libgcc/config/arm/bpabi.c
+++ b/libgcc/config/arm/bpabi.c
@@ -26,9 +26,6 @@ extern long long __divdi3 (long long, long long);
extern unsigned long long __udivdi3 (unsigned long long,
unsigned long long);
extern long long __gnu_ldivmod_helper (long long, long long, long long *);
-extern unsigned long long __gnu_uldivmod_helper (unsigned long long,
- unsigned long long,
- unsigned long long *);
long long
@@ -43,14 +40,3 @@ __gnu_ldivmod_helper (long long a,
return quotient;
}
-unsigned long long
-__gnu_uldivmod_helper (unsigned long long a,
- unsigned long long b,
- unsigned long long *remainder)
-{
- unsigned long long quotient;
-
- quotient = __udivdi3 (a, b);
- *remainder = a - b * quotient;
- return quotient;
-}
--
1.9.1
