在MSP430汇编器中使用十六进制数字

Question

I'm new to assembly (we are using it at school with an MSP430 controller) and I'm trying to do two things.

1. moving an hex number to a certain location: mov #FFFh, R5 (moving it into the fifth register)
2. comparing an hex number with another: cmp #FFFh, #45

            mov.b #0, R4 ; indice
            mov.b #0, R5 ; contatore

            bis.b #00000001b, P1DIR ; led rosso
            bis.b #10000000b, P4DIR    ; led verde

main_loop:  cmp #19, R5
            jz end
            cmp #FFFFh, 2C00h(R4)
            jnz nope
            jmp yep

nope:       inc.b R4
            jmp main_loop

yep:        inc.b R4
            inc.b R5
            jmp main_loop

end:        cmp #5, R5
            jge red_led
            jmp green_led

red_led:    bis.b #00000001b, P1OUT
green_led:  bis.b #10000000b, P4OUT

The compiler log (we are using CCS, CodeComposer) says:

"../main.asm", ERROR! at EOF: [E0300] The following symbols are undefined:
FFFFh

How can I fix this?

Answer 1

A word starting with a digit ( 0 … 9 ) is interpreted as a number.
A word starting with a letter ( A … Z ) is interpreted as a name (of a register or a variable or a label).

So when a hexadecimal number starts with a letter, you must add a zero:

        cmp #0FFFFh, 2C00h(R4)