diff options
Diffstat (limited to 'kernel/arch/h8300/lib/mulsi3.S')
| -rw-r--r-- | kernel/arch/h8300/lib/mulsi3.S | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/kernel/arch/h8300/lib/mulsi3.S b/kernel/arch/h8300/lib/mulsi3.S new file mode 100644 index 000000000..451f0e053 --- /dev/null +++ b/kernel/arch/h8300/lib/mulsi3.S @@ -0,0 +1,38 @@ +; +; mulsi3 for H8/300H - based on Renesas SH implementation +; +; by Toshiyasu Morita +; +; Old code: +; +; 16b * 16b = 372 states (worst case) +; 32b * 32b = 724 states (worst case) +; +; New code: +; +; 16b * 16b = 48 states +; 16b * 32b = 72 states +; 32b * 32b = 92 states +; + + .global __mulsi3 +__mulsi3: + mov.w r1,r2 ; ( 2 states) b * d + mulxu r0,er2 ; (22 states) + + mov.w e0,r3 ; ( 2 states) a * d + beq L_skip1 ; ( 4 states) + mulxu r1,er3 ; (22 states) + add.w r3,e2 ; ( 2 states) + +L_skip1: + mov.w e1,r3 ; ( 2 states) c * b + beq L_skip2 ; ( 4 states) + mulxu r0,er3 ; (22 states) + add.w r3,e2 ; ( 2 states) + +L_skip2: + mov.l er2,er0 ; ( 2 states) + rts ; (10 states) + + .end |