What does %P1 mean in gcc inline assembly?

[张云]

Hi

In /arch/x86/boot/main.c  (http://lxr.free-electrons.com/source/arch/x86/boot/main.c) ,

In the function init_heap,
asm("leal %P1(%%esp),%0"
122 <http://lxr.free-electrons.com/source/arch/x86/boot/source/arch/x86/boot/main.c#L122>                     : "=r" (stack_end) : "i" (-STACK_SIZE <http://lxr.free-electrons.com/source/arch/x86/boot/ident?i=STACK_SIZE>));
 What does the ‘%P1’ mean in the inline assembly above ?

Thanks !
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