Difference between revisions of "ARM: 64 bit operations"

Revision as of 00:32, 4 November 2007

Logical shift left by Rn (0-32)

       ;R0 - least significant word
       ;R1 - most significant word
       ;R2 - shift
       ;Uses R0-R3
       ;7 cycles constant
       mov	r1,r1,lsl r2
       rsb	r3,r2,#32
       orr	r1,1,r0,lsr r3
       mov	r0,r0,lsl r2

Logical shift left by Rn (0-64)

;R0 - least significant word ;R1 - most significant word ;R2 - shift ;Uses R0-R3 ; 8-9 cycles rsbs r3,r2,#32 submi r3,r2,#32 movmi r1,r0,lsl r3 movpl r1,r1,lsl r2 orrpl r1,r1,r0,lsr r3 mov r0,r0,lsl r2

Logical shift left by #n (0-32)

       ;R0 - least significant word
       ;R1 - most significant word
       ;Uses R0-R1
       ;3 cycles constant
       mov	r1,r1,lsl #n
       orr	r1,r1,r0,lsr #32-n
       mov	r0,r0,lsl #n

Logical shift left by #n (33-64)

;R0 - least significant word ;R1 - most significant word ;Uses R0-R1 ;2 cycles constant mov r1,r0,lsl #n-32 mov r0,#0

Logical shift left by 1

       ;R0 - least significant word
       ;R1 - most significant word
       ;Uses R0-R1
       ;2 cycles constant
       adds	r0,r0,r0
       adc	r1,r1,r1