Why won't this code assemble $($AT&T syntax$)$:

$.$section $.$bss

$.$lcomm input$\_$num, $2$

$.$section $.$data

format: $.$string $"$x$=\%$d : f$($x$)=\%$d or $0$x$\%$x

$\backslash 0"$

$.$section $.$text

$.$global $\_$start

main:

#Read two charcter from stdin

movq $$0,\%$rax #syscall number

movq $$0,\%$rdi #stdin

movq $input$\_$num, $\%$rsi #buffer to store input

movq $$2,\%$rdx #number of bytes to read

syscall

#Convert ASCII digits to interger

movzbl input$\_$num, $\%$eax

sub $$\text{'}0\text{'},\%$eax

imul $$10,\%$eax, $\%$eax

movzbl input$\_$num$+1,\%$ebx

sub $$\text{'}0\text{'},\%$ebx

add $\%$ebx, $\%$eax

#Store integer in $\%$ebx

movq $\%$eax, $\%$ebx

#$27$x $+17$

imul $$27,\%$eax, $\%$eax

add $$17,\%$eax

#Prepare for printf

movq $\%$ebx, $\%$edi #first argument $-$ x

movq $\%$eax, $\%$esi #second arugment $-$ f$($x$)$

movq $\%$eax, $\%$edx #third argument $-$ f$($x$)$ in hex

lea format, $\%$rdi #format string

#Call printf

movq $$0,\%$rax #syscall for sys$\_$write

call printf

#Exit

movq $$60,\%$rax #syscall for sys$\_$exit

movq $$0,\%$rdi #status $=0$

syscall