1b and 1f in the GNU assembly

Question

I am analyzing linux exception code. By the way, I can not understand the syntax of the gnu assembly.

    svc_preempt:
    mov r8, lr
1:  bl  preempt_schedule_irq        @ irq en/disable is done inside
    ldr r0, [tsk, #TI_FLAGS]        @ get new tasks TI_FLAGS
    tst r0, #_TIF_NEED_RESCHED
    moveq   pc, r8              @ go again
    b   1b

In this code, I see "b 1b", but I can not find the shortcut "1b" anywhere.

and

#ifdef CONFIG_NEON
    adr r6, .LCneon_thumb_opcodes
    b   2f
#endif
call_fpe:
#ifdef CONFIG_NEON
    adr r6, .LCneon_arm_opcodes
2:
    ldr r7, [r6], #4            @ mask value
    cmp r7, #0              @ end mask?
    beq 1f
    and r8, r0, r7
    ldr r7, [r6], #4            @ opcode bits matching in mask
    cmp r8, r7              @ NEON instruction?
    bne 2b
    get_thread_info r10
    mov r7, #1
    strb    r7, [r10, #TI_USED_CP + 10] @ mark CP#10 as used
    strb    r7, [r10, #TI_USED_CP + 11] @ mark CP#11 as used
    b   do_vfp              @ let VFP handler handle this
1:

I can not find the labels "2f" and "1f".

So, I am interested in the meaning of "1b", "1f", "2f", etc.

Answer 1

The shortcuts "xb" and "xf", where "x" is the number, are an intelligent extension to the GNU build. It branches to the first “x” found to search for “forward” for “f” or “back” for “b”.

, "1b" "1" , . "2f" "2" , , "2b" "2", .

.

. https://sourceware.org/binutils/docs-2.24/as/Symbol-Names.html#Symbol-Names - " ".

Answer 2

( ), . - , , - , "-" 1, - .

IBM370 - , !