我已经成功地打开了一个文件，并将文件描述符（7）存储在FILE中，并且我也有SIZE中存储的文件大小（153kb）。 这就是说，这个mmap系统调用返回一个-14。 我不确定我做错了什么
push %esi #Save non-general-purpose registers push %edi #Save non-general-purpose registers push %ebp #Save non-general-purpose registers movl FILE, %edi #Move file descriptor into edi movl $0, %ebp #Offset to 0 movl $0x2, %esi #MAP_PRIVATE movl $0x3, %edx #PROT_READ movl FSIZE, %ecx #File length movl $0, %ebx # *addr = NULL movl $90, %eax #mmap Sys Call int $0x80 #Call kernel test %eax, %eax #Error check js _error MMAP 90 = $ 5A
使用带有Intel-Syntax的NASM的MMAP framebuffer设备fb0的示例
%define XRes 400h %define YRes 300h %define Mapsize (XRes*YRes*4) ; 1024x768x32 section .text call MAP_FB ; mmap ;----------- Subroutine---- MAP_FB: mov eax, 5 ; syscall nr: open xor edx, edx mov ebx, DEVICE ; pointer/offset auf File/Device-Name mov ecx, 2 ; /usr/include/bits/fcntl.h = O_RDWR int 80h mov [FD], eax ; File discriptor mov ebx, MMAP mov eax, 5Ah ; mmap(90) int 80h mov esi, eax ; pointer mmap-FRAMEBUFFER ret section .data DEVICE DB "/dev/fb0", 0, 0, 0, 0 MMAP: DD 0 ; start - suggest memory address to allocate DD Mapsize ; length DD 3 ; prot (PROT_READ + PROT_WRITE) DD 1 ; flags (MAP_SHARED = 1) FD: DD 0 ; file discriptor(handle) DD 0 ; offset into file to start reading