Strange execution behaviour on NXP LPC2478

Hi, i hope someone can help me,

I want to recreate a J1850 communication. I have to generate changes on an output pin that have to come with intervals from 7,5 to 48 micro seconds.

so i have to generate very accurate delay times.

first i tried with counters and i failed (maybe for the same reason explained under), so i have used something like this:

                ...
        J1850SW_TX_DOMINANT();          // macro: move pin down
        Time = J1850SW_TSOF_DOMINANT;   // 198 right number found with oscilloscope ()
        while(Time) { __nop(); Time--; }
        J1850SW_TX_PASSIVE();           // macro: move pin up
        Time = J1850SW_TSOF_PASSIVE;    // 146 right number found with oscilloscope ()
        while(Time) { __nop(); Time--; }
                ...

yes, i know that is not sure that compiler will translate every time in the same way.

so i generate a .s assembly file:

        MOV      r0,#0x20000      // move pin down
        LDR      r1,|L1.1140|
        STR      r0,[r1,#0x98]
        MOV      r0,#0x80000000
        STR      r0,[r1,#0x9c]

        MOV      r0,r0
        MOV      r6,#0xc6
        B        |L1.276|
|L1.260|
        MOV      r0,r0
        SUB      r0,r6,#1
        LSL      r6,r0,#16
        LSR      r6,r6,#16
|L1.276|
        CMP      r6,#0
        BNE      |L1.260|

        MOV      r0,r0

        MOV      r0,#0x20000      // move pin up
        LDR      r1,|L1.1140|
        STR      r0,[r1,#0x9c]
        MOV      r0,#0x80000000
        STR      r0,[r1,#0x98]

        MOV      r0,r0
        MOV      r6,#0x92
        B        |L1.336|
|L1.320|
        MOV      r0,r0
        SUB      r0,r6,#1
        LSL      r6,r0,#16
        LSR      r6,r6,#16
|L1.336|
        CMP      r6,#0
        BNE      |L1.320|

and then i imported in the keil project the .o file object directly. it is possible and it works.
every time i compile, the code is always the same.

what's the problem, you'll say!

the problem is that if i change the linking order of the file, delay change...
interrupt are all disable, no call is made from the source file to functions in other file...

so why this behaviour? how it is possible that linking order affect code execution?
maybe the sector in wich code is executing?

if i don't know what's the problem, i cannot be sure that source will always work.

thanks for all answers