有符号除法运算
Signed Divide divides a signed integer register value by another signed integer register value, and writes the result to the destination register. The condition flags are not affected.
将一个有符号整数寄存器值除以另一个有符号整数寄存器值，并将结果写入目标寄存器。条件标志不受影响。
32-bit variant
Applies when sf == 0.
SDIV <Wd>, <Wn>, <Wm>
64-bit variant
Applies when sf == 1.
SDIV <Xd>, <Xn>, <Xm>
403f14: b9405a7a ldr w26, [x19, #88]
403f18: 340002fa cbz w26, 403f74 <ferror@plt+0x2094>
403f1c: 52800020 mov w0, #0x1 // #1
403f20: 2a0003fb mov w27, w0
403f24: 0b000800 add w0, w0, w0, lsl #2
403f28: 531f7800 lsl w0, w0, #1
403f2c: 1ac00f42 sdiv w2, w26, w0
403f30: 35ffff82 cbnz w2, 403f20 <ferror@plt+0x2040>
