diff options
| -rw-r--r-- | libcpu/ti-dsp/c28x/context.s | 22 | ||||
| -rw-r--r-- | libcpu/ti-dsp/c28x/cpuport.c | 15 |
2 files changed, 37 insertions, 0 deletions
diff --git a/libcpu/ti-dsp/c28x/context.s b/libcpu/ti-dsp/c28x/context.s index f0555d6d35..f21e0ddb6e 100644 --- a/libcpu/ti-dsp/c28x/context.s +++ b/libcpu/ti-dsp/c28x/context.s @@ -6,6 +6,8 @@ ; Change Logs: ; Date Author Notes ; 2018-09-01 xuzhuoyi the first version. +; 2019-06-17 zhaoxiaowei fix bugs of old c28x interrupt api. +; 2019-07-03 zhaoxiaowei add _rt_hw_calc_csb function to support __rt_ffs. ; .ref _rt_interrupt_to_thread @@ -15,6 +17,7 @@ .def _RTOSINT_Handler .def _rt_hw_get_st0 .def _rt_hw_get_st1 + .def _rt_hw_calc_csb .def _rt_hw_context_switch_interrupt .def _rt_hw_context_switch .def _rt_hw_context_switch_to @@ -229,6 +232,25 @@ _rt_hw_get_st1: LRETR .endasmfunc +; C28x do not have a build-in "__ffs" func in its C compiler. +; We can use the "Count Sign Bits" (CSB) instruction to make one. +; CSB will return the number of 0's minus 1 above the highest set bit. +; The count is placed in T. For example: +; ACC T maxbit +; 0x00000001 30 0 +; 0x00000010 26 4 +; 0x000001FF 22 8 +; 0x000001F0 22 8 + .asmfunc +_rt_hw_calc_csb: + MOV AH, #0 + CSB ACC ; T = no. of sign bits - 1 + MOVU ACC, T ; ACC = no. of sign bits - 1 + SUBB ACC, #30 ; ACC = ACC - 30 + ABS ACC ; ACC = |ACC| + lretr + .endasmfunc + ; ; * void rt_hw_context_switch_to(rt_uint32 to); ; * r0 --> to diff --git a/libcpu/ti-dsp/c28x/cpuport.c b/libcpu/ti-dsp/c28x/cpuport.c index 2d42884bed..e34556c524 100644 --- a/libcpu/ti-dsp/c28x/cpuport.c +++ b/libcpu/ti-dsp/c28x/cpuport.c @@ -6,6 +6,7 @@ * Change Logs: * Date Author Notes * 2018-09-01 xuzhuoyi the first version. + * 2019-07-03 zhaoxiaowei add support for __rt_ffs. */ #include <rtthread.h> @@ -19,6 +20,7 @@ static rt_err_t (*rt_exception_hook)(void *context) = RT_NULL; extern rt_uint16_t rt_hw_get_st0(void); extern rt_uint16_t rt_hw_get_st1(void); +extern int rt_hw_calc_csb(int value); struct exception_stack_frame { @@ -102,6 +104,19 @@ struct exception_info struct stack_frame stack_frame; }; +#ifdef RT_USING_CPU_FFS +/* + * This function called rt_hw_calc_csb to finds the first bit set in value. + * rt_hw_calc_csb is a native assembly program that use "CSB" instruction in C28x. + * When you use this function, remember that "int" is only 16-bit in C28x's C compiler. + * If value is a number bigger that 0xFFFF, trouble may be caused. + * Maybe change "int __rt_ffs(int value)" to "rt_int32_t __rt_ffs(rt_int32_t value)" will be better. + */ +int __rt_ffs(int value) +{ + return rt_hw_calc_csb(value); +} +#endif /** * shutdown CPU |