Problem with increment in inline ARM assembly
- by tech74
Hi , i have the following bit of inline ARM assembly, it works in a debug build but crashes in a release build of iphone sdk 3.1. The problem is the add instructions where i am incrementing the address of the C variables output and x by 4 bytes, this is supposed to increment by the size of a float. I think when i increment at some such stage i am overwriting something, can anyone say which is the best way to handle this
Thanks
C code that the asm is replacing, sum,output and x are all floats
for(int i = 0; i< count; i++)
sum+= output[i]* (*x++)
asm volatile(
".align 4 \n\t"
"mov r4,%3 \n\t"
"flds s0,[%0] \n\t"
"0: \n\t"
"flds s1,[%2] \n\t"
//"add %3,%3,#4 \n\t"
"flds s2,[%1] \n\t"
//"add %2,%2,#4 \n\t"
"subs r4,r4, #1 \n\t"
"fmacs s0, s1, s2 \n\t"
"bne 0b \n\t"
"fsts s0,[%0] \n\t"
:
: "r" (&sum), "r" (output), "r" (x),"r" (count)
: "r0","r4","cc", "memory",
"s0","s1","s2"
);
