e300 (MPC5121) dlmzb

[Fortini Matteo]

I was trying to insert an optimized strlen() function using the 
following code taken from the ibm site on an MPC5121, but it crashes the 
kernel.
Is it because it's an unsupported op, or because I'm missing some needed 
steps?

Thank you,
Matteo

_GLOBAL(strlen)
    addi   r4,0,8    // Load byte count of 8
    mtxer  r4        // Set byte count for load string
    xor    r4,r4,r4  // r4 = 0, r4 == accumulator
1:
    lswx   r5,r3,r4  // load string into r5 & r6
    dlmzb. r12,r5,r6 // find NULL byte and record in r7.
    add    r4,r4,r12 // Update accumulator.
    beq    1b        // Loop if NULL not found.
    addi   r3,r4,-1  // Subtract 1 for NULL byte.
    blr              // Return length