linux环境下修改linux0.11 bootsect.s并用qemu运行的问题

看了bootsect.s，我想在linux下直接编译，并用qemu 模拟器运行，但是有问题，我将代码最简化，发现可能是段间跳转和ds,es寄存器设置的问题，请帮忙看下是哪里不对，谢谢了，问题描述如下：
bootsect.s的代码：
.set BOOTSEG, 0x07c0
.set INITSEG, 0x9000

.globl start
start:
.code16

# print some inane message
  movw $0x0300,%ax #read cursor position
  xorb %bh,%bh
  int $0x10

  movw $28,%cx
  movw $0x0004,%bx
  movw $msg,%bp
  movw $0x1301,%ax # write string and move cursor
  int $0x10

# mov this sector to 0x9000 and then jmp to next instruction
  movw $BOOTSEG, %ax
  movw %ax, %ds # source addr ds:si
  movw $INITSEG, %ax
  movw %ax, %es # dest addr es:di
  xorw %si, %si
  xorw %di, %di
  movw $256, %cx # 256 *2 = 512 bytes
  rep
  movsw
  ljmp $INITSEG, $go

go:
  movw $0x0300,%ax #read cursor position
  xorb %bh,%bh
  int $0x10

  movw $28,%cx
  movw $0x0004,%bx
  movw $msg,%bp
  movw $0x1301,%ax # write string and move cursor
  int $0x10



loop:
  jmp loop

msg:
  .byte 13, 10 #CR LF carriage returns line feeds
  .ascii "Loading system ... ^_^"
  .byte 13, 10, 13, 10

.org 510
  .word 0xaa55

用了shell脚本来编译make.sh:
as bootsect.s -o bootsect
ld -m elf_i386 -N -e start -Ttext 0x7c00 bootsect -o bootblock
objcopy -S -O binary bootblock
qemu -hda bootblock
问题：我是想显示 Loading system ... 然后将这个启动扇区移动到0x9000处跳到标号go并重新显示Loading system ...以验证移动成功，但是，只能显示第一次的Loading system ...，如果没有中间的那段移动启动扇区的代码，那么能够显示两次Loading system ...，请大家看下是哪里的问题，谢谢:)

1. ljmp $INITSEG, $go 执行的时候是jmp far 9000:7c30，问题就来了，只是复制到了0x9000:0处，而9000:7c30处全是0，跳转过去肯定不对了，应该是ljmp $INITSEG, $0x30才对，这里的0x30就是0x7c30-0x7c00得出来的
2. 在做扇区移动的时候es的值被改为了9000，当调用执行int 0x10的时候，es:bp指向的地方是没有数据的，仍然全是0
3. bios 0x10号中断的0x13号功能应该要设置"DH,DL=起始行,列"，你的代码里好像没有呢。
PS: 你可以用bochs去debug这个bootsector，问题出在哪里很容易发现的
修改后的代码：
Assembly code

.set BOOTSEG, 0x07c0
.set INITSEG, 0x9000

.globl start
start:
.code16

# print some inane message
  movw $0x0300,%ax #read cursor position
  xorb %bh,%bh
  int $0x10

  movw $28,%cx
  [color=#FF0000]movw $0x0, %dx[/color]
  movw $0x0004,%bx
  movw $msg,%bp
  movw $0x1301,%ax # write string and move cursor
  int $0x10

# mov this sector to 0x9000 and then jmp to next instruction
  movw $BOOTSEG, %ax
  movw %ax, %ds # source addr ds:si
  movw $INITSEG, %ax
  movw %ax, %es # dest addr es:di
  xorw %si, %si
  xorw %di, %di
  movw $256, %cx # 256 *2 = 512 bytes
  rep
  movsw
  [color=#FF0000]ljmp $INITSEG, $0x30[/color]

go:
  [color=#FF0000]movw $0, %ax
  movw %ax, %es[/color]
  movw $0x0300,%ax #read cursor position
  xorb %bh,%bh
  int $0x10
  
  movw $28,%cx
  movw $0x0004,%bx
  [color=#FF0000]movw $0x0100, %dx[/color]
  movw $msg,%bp
  movw $0x1301,%ax # write string and move cursor
  int $0x10



loop:
  jmp loop

msg:
  .byte 13, 10 #CR LF carriage returns line feeds
  .ascii "Loading system ... ^_^"
  .byte 13, 10, 13, 10

.org 510
  .word 0xaa55

我晕，红色字体显示代码居然不好用，重贴一次：
Assembly code

.set BOOTSEG, 0x07c0
.set INITSEG, 0x9000

.globl start
start:
.code16

# print some inane message
  movw $0x0300,%ax #read cursor position
  xorb %bh,%bh
  int $0x10

  movw $28,%cx
  movw $0x0, %dx
  movw $0x0004,%bx
  movw $msg,%bp
  movw $0x1301,%ax # write string and move cursor
  int $0x10

# mov this sector to 0x9000 and then jmp to next instruction
  movw $BOOTSEG, %ax
  movw %ax, %ds # source addr ds:si
  movw $INITSEG, %ax
  movw %ax, %es # dest addr es:di
  xorw %si, %si
  xorw %di, %di
  movw $256, %cx # 256 *2 = 512 bytes
  rep
  movsw
  ljmp $INITSEG, $0x30

go:
  movw $0, %ax
  movw %ax, %es
  movw $0x0300,%ax #read cursor position
  xorb %bh,%bh
  int $0x10

  movw $28,%cx
  movw $0x0004,%bx
  movw $0x0100, %dx
  movw $msg,%bp
  movw $0x1301,%ax # write string and move cursor
  int $0x10



loop:
  jmp loop

msg:
  .byte 13, 10 #CR LF carriage returns line feeds
  .ascii "Loading system ... ^_^"
  .byte 13, 10, 13, 10

.org 510
  .word 0xaa55