From: Georg-Johann Lay <avr@gjlay.de>
Date: Fri, 4 Apr 2025 20:01:43 +0000 (+0200)
Subject: AVR: Speed up __umulhisi3 for small devices with MUL.
X-Git-Tag: basepoints/gcc-16~332
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6753df43a0251cffbfe2fca85e978807f976fb01;p=thirdparty%2Fgcc.git

AVR: Speed up __umulhisi3 for small devices with MUL.

__umulhisi3 had an "rcall 1f" to save 6 bytes, which is an unreasonable
size gain vs. cycle cost.  Just use the same code on all devices with MUL,
irrespective of program memory size.

libgcc/
	* config/avr/lib1funcs.S (__umulhisi3) [Have MUL]: Reduce call
	depth by 1.
---

diff --git a/libgcc/config/avr/lib1funcs.S b/libgcc/config/avr/lib1funcs.S
index 96f20ca8e64..01208927c6b 100644
--- a/libgcc/config/avr/lib1funcs.S
+++ b/libgcc/config/avr/lib1funcs.S
@@ -581,19 +581,12 @@ DEFUN __umulhisi3
     mul     A1, B1
     movw    C2, r0
     mul     A0, B1
-#ifdef __AVR_HAVE_JMP_CALL__
-    ;; This function is used by many other routines, often multiple times.
-    ;; Therefore, if the flash size is not too limited, avoid the RCALL
-    ;; and inverst 6 Bytes to speed things up.
     add     C1, r0
     adc     C2, r1
     clr     __zero_reg__
     adc     C3, __zero_reg__
-#else
-    rcall   1f
-#endif
     mul     A1, B0
-1:  add     C1, r0
+    add     C1, r0
     adc     C2, r1
     clr     __zero_reg__
     adc     C3, __zero_reg__