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AVR: target/114835 - Tweak popcountqi2

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libgcc/
	PR target/114835
	* config/avr/lib1funcs.S (__popcountqi2): Use code that
	is one instruction shorter / faster.
This commit is contained in:
Wolfgang Hospital 2024-05-07 16:24:39 +02:00 committed by Georg-Johann Lay
parent 3f04f3939e
commit 8d2c93fcfe
1 changed files with 15 additions and 15 deletions
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30
libgcc/config/avr/lib1funcs.S
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@ -3050,21 +3050,21 @@ ENDF __popcountdi2
;; r24 = popcount8 (r24)
;; clobbers: __tmp_reg__
DEFUN __popcountqi2
mov __tmp_reg__, r24
andi r24, 1
lsr __tmp_reg__
lsr __tmp_reg__
adc r24, __zero_reg__
lsr __tmp_reg__
adc r24, __zero_reg__
lsr __tmp_reg__
adc r24, __zero_reg__
lsr __tmp_reg__
adc r24, __zero_reg__
lsr __tmp_reg__
adc r24, __zero_reg__
lsr __tmp_reg__
adc r24, __tmp_reg__
mov __tmp_reg__, r24 ; oeoeoeoe
andi r24, 0xAA ; o0o0o0o0
lsr r24 ; 0o0o0o0o
;; Four values 0, 1 or 2: # bits set o+e
sub __tmp_reg__, r24 ; 44332211
mov r24, __tmp_reg__ ; 44332211
andi r24, 0x33 ; 00330011
eor __tmp_reg__, r24 ; 44002200
lsr __tmp_reg__ ; 04400220
lsr __tmp_reg__ ; 00440022
add r24, __tmp_reg__ ; 04210421
mov __tmp_reg__, r24 ; h421l421
swap __tmp_reg__ ; l421h421
add r24, __tmp_reg__ ; 84218421
andi r24, 0xf ; 00008421 /17
ret
ENDF __popcountqi2
#endif /* defined (L_popcountqi2) */