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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.2.2/] [gcc/] [config/] [sh/] [divcost-analysis] - Rev 414
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Analysis of cycle costs for SH4:
-> udiv_le128: 5
-> udiv_ge64k: 6
-> udiv udiv_25: 10
-> pos_divisor: 3
-> pos_result linear: 5
-> pos_result - -: 5
-> div_le128: 7
-> div_ge64k: 9
sdivsi3 -> udiv_25 13
udiv25 -> div_ge64k_end: 15
div_ge64k_end -> rts: 13
div_le128 -> div_le128_2: 2, r1 latency 3
udiv_le128 -> div_le128_2: 2, r1 latency 3
(u)div_le128 -> div_by_1: 9
(u)div_le128 -> rts: 17
div_by_1(_neg) -> rts: 4
div_ge64k -> div_r8: 2
div_ge64k -> div_ge64k_2: 3
udiv_ge64k -> udiv_r8: 3
udiv_ge64k -> div_ge64k_2: 3 + LS
(u)div_ge64k -> div_ge64k_end: 13
div_r8 -> div_r8_2: 2
udiv_r8 -> div_r8_2: 2 + LS
(u)div_r8 -> rts: 21
-> - + neg_result: 5
-> + - neg_result: 5
-> div_le128_neg: 7
-> div_ge64k_neg: 9
-> div_r8_neg: 11
-> <64k div_ge64k_neg_end: 28
-> >=64k div_ge64k_neg_end: 22
div_ge64k_neg_end ft -> rts: 14
div_r8_neg_end -> rts: 4
div_r8_neg -> div_r8_neg_end: 18
div_le128_neg -> div_by_1_neg: 4
div_le128_neg -> rts 18
absolute divisor range:
1 [2..128] [129..64K) [64K..|divident|/256] >=64K,>|divident/256|
udiv 18 22 38 32 30
sdiv pos: 20 24 41 35 32
sdiv neg: 15 25 42 36 33
fp-based:
unsigned: 42 + 3 + 3 (lingering ftrc latency + sts fpul,rx) at caller's site
signed: 33 + 3 + 3 (lingering ftrc latency + sts fpul,rx) at caller's site
call-div1: divisor range:
[1..64K) >= 64K
unsigned: 63 58
signed: 76 76
SFUNC_STATIC call overhead:
mov.l 0f,r1
bsrf r1
SFUNC_GOT call overhead - current:
mov.l 0f,r1
mova 0f,r0
mov.l 1f,r2
add r1,r0
mov.l @(r0,r2),r0
jmp @r0
; 3 cycles worse than SFUNC_STATIC
SFUNC_GOT call overhead - improved assembler:
mov.l 0f,r1
mova 0f,r0
mov.l @(r0,r1),r0
jmp @r0
; 2 cycles worse than SFUNC_STATIC
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