arch/mips/kernel/head.S
本帖最后由 torchof2008 于 2015-02-08 14:13 编辑arch/mips/kernel/head.S中设置setup_c0_status时的
.macro setup_c0_status set clr
.set push
#ifdef CONFIG_MIPS_MT_SMTC
/*
* For SMTC, we need to set privilege and disable interrupts only for
* the current TC, using the TCStatus register.
*/
mfc0 t0, CP0_TCSTATUS
/* Fortunately CU 0 is in the same place in both registers */
/* Set TCU0, TMX, TKSU (for later inversion) and IXMT */
li t1, ST0_CU0 | 0x08001c00
or t0, t1
/* Clear TKSU, leave IXMT */
xori t0, 0x00001800
mtc0 t0, CP0_TCSTATUS
_ehb
/* We need to leave the global IE bit set, but clear EXL...*/
mfc0 t0, CP0_STATUS
or t0, ST0_CU0 | ST0_EXL | ST0_ERL | \set | \clr
xor t0, ST0_EXL | ST0_ERL | \clr
mtc0 t0, CP0_STATUS
#else
mfc0 t0, CP0_STATUS
or t0, ST0_CU0|\set|0x1f|\clr
xor t0, 0x1f|\clr
mtc0 t0, CP0_STATUS
.set noreorder
sll zero,3 # ehb
#endif
.set pop
.endm
上面代码中，setup_c0_status set clr中的 set clr和| \set | \clr、|\set|0x1f|\clr是什么意思呢？查了一些资料没有找到答案，麻烦知道的网友解答一些。谢谢~~
就是宏展开。
例如setup_c0_status 10 20中的
or t0, ST0_CU0|\set|0x1f|\clr
就成了
or t0, ST0_CU0|10|0x1f|20
这些东西没什么资料，看看基本这么回事就行了。关于mips最好的书是see mips run，可以看看
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