118 lines
1.6 KiB
C
118 lines
1.6 KiB
C
// 一些常用的、共用的接口
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/*
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* 将指定寄存器的指定位置1
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* @reg 寄存器地址
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* @bit 需要置1的那一bit
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*/
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void reg_set_one_bit(volatile unsigned int *reg, unsigned int bit)
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{
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unsigned int temp, mask;
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mask = 1 << bit;
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temp = *reg;
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temp |= mask;
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*reg = temp;
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return ;
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}
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/*
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* 将指定寄存器的指定位清零
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* @reg 寄存器地址
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* @bit 需要清零的那一bit
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*/
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void reg_clr_one_bit(volatile unsigned int *reg, unsigned int bit)
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{
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unsigned int temp, mask;
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mask = 1 << bit;
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temp = *reg;
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temp &= ~mask;
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*reg = temp;
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return ;
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}
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/*
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* 获取指定寄存器的指定位的值
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* @reg 寄存器地址
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* @bit 需要读取值的那一bit
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* @ret 指定位的值
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*/
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unsigned int reg_get_bit(volatile unsigned int *reg, unsigned int bit)
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{
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unsigned int temp;
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temp = *reg;
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temp = (temp >> bit) & 1;
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return temp;
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}
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/*
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* 向寄存器中写一个32bit的数据
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* @data 待写入的数据
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* @addr 寄存器地址
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*/
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void reg_write_32(unsigned int data, volatile unsigned int *addr)
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{
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*addr = data;
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}
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/*
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* 从寄存器读出一个32bit数据
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* @addr 寄存器地址
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* @ret 读出的数据
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*/
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unsigned int reg_read_32(volatile unsigned int *addr)
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{
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return (*addr);
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}
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/**
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* ffs - find first bit set
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* @x: the word to search
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*
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* This is defined the same way as
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from the above ffz (man ffs).
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*/
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int ls1c_ffs(int x)
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{
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int r = 1;
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if (!x)
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return 0;
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if (!(x & 0xffff)) {
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x >>= 16;
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r += 16;
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}
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if (!(x & 0xff)) {
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x >>= 8;
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r += 8;
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}
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if (!(x & 0xf)) {
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x >>= 4;
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r += 4;
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}
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if (!(x & 3)) {
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x >>= 2;
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r += 2;
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}
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if (!(x & 1)) {
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x >>= 1;
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r += 1;
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}
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return r;
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}
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