Implementation in NEON of non uniform address jumps

A maxVal of 255 may well map onto a single instruction.

5.12.5. VLDn and VSTn (multiple n-element structures)
Vector Load multiple n-element structures. It loads multiple n-element structures from memory into one or more NEON registers, with de-interleaving (unless n == 1). Every element of each register is loaded.

Vector Store multiple n-element structures. It stores multiple n-element structures to memory from one or more NEON registers, with interleaving (unless n == 1). Every element of each register is stored.


Syntax
Vopn{cond}.datatype list, [Rn{@align}]{!}
Vopn{cond}.datatype list, [Rn{@align}], Rm
where:

[i]op [/i]must be either LD or ST.

[i]n [/i]must be one of 1, 2, 3, or 4.

[i]cond [/i]is an optional condition code (see Condition codes).

[i]datatype [/i]see Table 5.14 for options.

[i]list [/i]specifies the NEON register list. See Table 5.14 for options.

[i]Rn [/i]is the ARM register containing the base address. Rn cannot be r15.

[i]align [/i]specifies an optional alignment. See Table 5.14 for options.

!if ! is present, Rn is updated to (Rn + the number of bytes transferred by the instruction). The update occurs after all the loads or stores have taken place.

[i]Rm [/i]is an ARM register containing an offset from the base address. If Rm is present, Rn is updated to (Rn + Rm) after the address is used to access memory. Rm cannot be r13 or r15.

Error: Neon quad precision register expected -- `vld1.16 q1,[ip],r4'

"cmp    %10,#1                            \n\t"//if(isLast)     
      "bne    3f                                \n\t"         
      "vmin.s32   d4,d4,d13                        \n\t"
      "vmax.s32   d4,d4,d12                        \n\t"
      "3:                                          \n\t"   

    //d13 contains maxVal(255)
    //d12 contains 0

Are you using "-mfloat-abi=softfp -mfpu=neon" on the GCC command line?

Also, you really might want to consider using the intrinsics instead of inline asm.