Haodong Wang wrote:
Hi,
Sometime I have a strange problem when I do jump in my assembly code
(embedded in C), the compiler always complains "Error: symbol 'L1' is
already defined". I changed the symbol, but it still complains the
same problem. Is that the bug in mspgcc? Any solution to get
around? Thanks!
" mov #1000, r8 \n"
"L1: \n"
" mov #1000, r9 \n"
......
" jnz L1 \n"
haodong
Defining L1 creates a symbol in the assembly language code with a fixed
name. If you do that more than once you will get an error tht the symbol
is already defined. If you try something like the following that doesn't
happen, as the actual names of the labels are generated dynamically (I
just grabbed a suitable example from my own source code. This does an
efficient Q1.15 multiply for machines with no hardware multiplier).
Steve
__asm__ (
" tst %[x] \n"
" jge 2f \n"
" mov #-1,%[x1] \n"
" jmp 2f \n"
"6: \n"
" add %[x],%A[z] \n"
" addc %[x1],%B[z] \n"
"1: \n"
" rla %[x] \n"
" rlc %[x1] \n"
"2: \n"
" rra %[y] \n"
" jc 5f \n"
" jne 1b \n"
" jmp 4f \n"
"5: \n"
" sub %[x],%A[z] \n"
" subc %[x1],%B[z] \n"
"3: \n"
" rla %[x] \n"
" rlc %[x1] \n"
" rra %[y] \n"
" jnc 6b \n"
" cmp #0xFFFF,%[y] \n"
" jne 3b \n"
"4: \n"
//Shift to Q1.15 format (i.e. the top 16 bits are returned)
" rla %A[z] \n"
" rlc %B[z] \n"
" mov %B[z],%[x1] \n"
: [z] "+r"(z), [x1] "+r"(x1)
: [x] "r"(x), [y] "r"(y));
