Subversion Repositories freemyipod

	.code 16

	.align 1

thumb_nrv2e_d8:

	mov r7,r2

        mov r4,#1; neg r5,r4 @ r5= -1 initial condition

        lsl r4,#31 @ 1<<31: refill next time

        mov r6,#5

        lsl r6,#8 @ 0x500 @ nrv2e M2_MAX_OFFSET

        b top_n2e

nrv2e_done:

	blx flushcache

	bx r7

get1_n2e: @ In: Carry set [from adding 0x80000000 (1<<31) to itself]

        ldrb r4,[r0] @ zero-extend next byte

        adc r4,r4 @ double and insert CarryIn as low bit

        add r0,#1

        lsl r4,#24 @ move to top byte, and set CarryOut from old bit 8

        mov pc,lr @ return, stay in current (THUMB) mode

lit_n2e:

        ldrb r3,[r0]; add r0,#1

        strb r3,[r2]; add r2,#1

top_n2e:

        add r4,r4; mov lr,pc; beq get1_n2e; bcs lit_n2e

        mov r1,#1; b getoff_n2e

off_n2e:

        sub r1,#1

        add r4,r4; mov lr,pc; beq get1_n2e; adc r1,r1

getoff_n2e:

        add r4,r4; mov lr,pc; beq get1_n2e; adc r1,r1

        add r4,r4; mov lr,pc; beq get1_n2e; bcc off_n2e

        sub r3,r1,#3 @ set Carry

        mov r1,#0 @ Carry unaffected

        blo offprev_n2e @ r1 was 2; tests Carry only

        lsl r3,#8

        ldrb r5,[r0]; add r0,#1 @ low 7+1 r4

        orr r5,r3

        mvn r5,r5; beq nrv2e_done @ r5= ~r5

        asr r5,#1; bcs lenlast_n2e

        b lenmore_n2e

offprev_n2e:

        add r4,r4; mov lr,pc; beq get1_n2e; bcs lenlast_n2e

lenmore_n2e:

        mov r1,#1

        add r4,r4; mov lr,pc; beq get1_n2e; bcs lenlast_n2e

len_n2e:

        add r4,r4; mov lr,pc; beq get1_n2e; adc r1,r1

        add r4,r4; mov lr,pc; beq get1_n2e; bcc len_n2e

        add r1,#6-2

        b gotlen_n2e

lenlast_n2e:

        add r4,r4; mov lr,pc; beq get1_n2e; adc r1,r1 @ 0,1,2,3

        add r1,#2

gotlen_n2e: @ 'cmn': add the inputs, set condition codes, discard the sum

        cmn r6,r5; bcs near_n2e @ within M2_MAX_OFFSET

        add r1,#1 @ too far away, so minimum match length is 3

near_n2e:

        ldrb r3,[r2] @ force cacheline allocate

copy_n2e:

        ldrb r3,[r2,r5]

        strb r3,[r2]; add r2,#1

        sub r1,#1; bne copy_n2e

        b top_n2e

	.code 32

	tst	r8, #0x20