Assembly ARM：浮点（VFP）指令赢得'；推入堆栈时不工作

我正在尝试在ARM汇编中打印一些浮点值。只要我不将内容推入堆栈，值就会正确打印。如果我按下某个按钮，它只会打印0

这段代码之所以有效，是因为它不会将内容推入堆栈

    .global main
    .func main

main:
  LDR R0, value_address @ Get address of value
  VLDR S14, [R0]        @ Move value into single precision S14 register
  VCVT.F64.F32 D0, S14  @ Convert single precision to double precision for printf

  LDR R0, =string       @ Give R0 the address of the string
  VMOV R2, R3, D0       @ Get the double precision value stored in registers
  BL printf             @ call printf

  MOV R7, #1            @ Exit syscall
  SWI 0

value_address:  .word value

.data
value:  .float 3.141592
string: .asciz "Floating point value is: %f\n"

我得到以下输出：

pi@raspberrypi:~/aal $ gcc -o printfp printfp.s
pi@raspberrypi:~/aal $ ./printfp
Floating point value is: 3.141592

然后我修改它以使用堆栈来保存

LR

，但它不能正常工作。我以前在没有VFP指令的情况下做过，它可以工作

    .global main
    .func main

main:
    PUSH {LR}

    LDR R0, value_address   @ Get address of value
    VLDR S14, [R0]          @ Move value into single precision S14 register
    VCVT.F64.F32 D0, S14    @ Convert single precision to double precision for printf

    LDR R0, =string         @ Give R0 the address of the string
    VMOV R2, R3, D0         @ Get the double precision value stored in registers
    BL printf               @ call printf

    POP {PC}
    BX LR

value_address:  .word value

.data
value:  .float 3.141592
string: .asciz "Floating point value is: %f\n"

现在我得到这个值：

pi@raspberrypi:~/aal $ gcc -o printfp printfp.s
pi@raspberrypi:~/aal $ ./printfp
Floating point value is: 0.000000

---

所以我不确定我做错了什么。有人能帮我吗

可能是堆栈未对齐问题吗？EABI要求堆栈8字节对齐。这可能是堆栈未对齐的问题吗？EABI要求堆栈对齐8字节。