2014-05-22 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
