GNU C中嵌入汇编添加一个自定义uboot命令

二话没用，直接上代码：

#include <common.h>#include <command.h>/*static inline int __raw_readsb(unsigned int addr, void *data, int bytelen){__asm__ __volatile__ ("1:ld.dir8, [r0]\n""sub.fr2, r2, 1\n""bnz.d1b\n""stb.abr8, [r1, 1]\n":: "r" (addr), "r" (data), "r" (bytelen): "r8");return bytelen;}static int disable_interrupts (void){    unsigned long old,temp;        __asm__ __volatile__("mrs %0, cpsr\n"     "orr %1, %0, #0x80\n"    "msr cpsr_c, %1"         : "=r" (old), "=r" (temp)    :        : "memory");    return (old & 0x80) == 0;}*/static void show_cache_state(void){unsigned long state;__asm__ volatile ("MRC p15, 0,%0, c1, c0, 0\n\r": "=r" (state):: "memory" );printf(" register SCTLR value: %lx \n", state );if(state & (0x01<<12)) {printf("Icache : ON\n");} else {printf("Icache : OFF\n");}if(state & (0x01<<2)) {printf("Dcache : ON\n");} else {printf("Icache : OFF\n");}}U_BOOT_CMD(nu_cache, 1, 0, show_cache_state,"show Icache and Dcache state","nu_cache [args...]\n");static void do_set_cache(unsigned int icase){unsigned long value,state;__asm__ volatile ("MRC p15, 0,%0, c1, c0, 0\n\r": "=r" (state):: "memory" );printf(" register SCTLR old value: %lx \n", state );switch (icase) {case 1:value = state & ~(0x01<<2);break;case 2:value = state | (0x01<<2);break;case 3:value = state & ~(0x01<<12);break;case 4:value = state | (0x01<<12);break;default:value = state;break;}printf(" the value will write to is: %#lx \n", value );__asm__ volatile ("MCR p15, 0,%0, c1, c0, 0\n\r": : "r" (value): "memory" );__asm__ volatile ("MRC p15, 0,%0, c1, c0, 0\n\r": "=r" (state):: "memory" );printf(" register SCTLR new value: %lx \n", state );}static int set_cache(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]){if(argc < 3) {printf("args eeror\n");return -1 ;}if( strcmp(argv[1],"-D")==0 ) {printf("set Dcache:");if( strcmp(argv[2],"0")==0 ) {do_set_cache(1);} else if( strcmp(argv[2],"1")==0 ) {do_set_cache(2);} else {printf("argv[2] must is 0 or 1 \n");return -1 ;}printf("\n");}else if( strcmp(argv[1],"-I")==0 ) {printf("set Icache:");if( strcmp(argv[2],"0")==0 ) {do_set_cache(3);} else if( strcmp(argv[2],"1")==0 ) {do_set_cache(4);} else {printf("argv[2] must is 0 or 1 \n");return -1 ;}printf("\n");}else {printf("argv[1] must be -D or -I\n");return -1;}return 0;}U_BOOT_CMD(nu_cache_set, 3, 2, set_cache,"set Icache and Dcache ","nu_cache_set [options]\n");