增加龙芯1c硬浮点的支持（可以使用硬浮点了）

bsp/ls1cdev/drivers/board.c

@@ -51,6 +51,31 @@ void rt_hw_timer_init(void)
 	write_c0_count(0);
 }
 
+
+/**
+ * init hardware FPU
+ */
+void rt_hw_fpu_init(void)
+{
+    rt_uint32_t c0_status = 0;
+    rt_uint32_t c1_status = 0;
+
+    // ʹЭ1--FPU
+    c0_status = read_c0_status();
+    c0_status |= (ST0_CU1 | ST0_FR);
+    write_c0_status(c0_status);
+
+    // FPU
+    c1_status = read_c1_status();
+    c1_status |= (FPU_CSR_FS | FPU_CSR_FO | FPU_CSR_FN);    // set FS, FO, FN
+    c1_status &= ~(FPU_CSR_ALL_E);                          // disable exception
+    c1_status = (c1_status & (~FPU_CSR_RM)) | FPU_CSR_RN;   // set RN
+    write_c1_status(c1_status);
+
+    return ;
+}
+
+
 /**
  * This function will initial sam7s64 board.
  */
@@ -69,6 +94,9 @@ void rt_hw_board_init(void)
 	/* init operating system timer */
 	rt_hw_timer_init();
 
+    /* init hardware fpu */
+    rt_hw_fpu_init();
+
 	rt_kprintf("current sr: 0x%08x\n", read_c0_status());
 }
 

libcpu/mips/common/mipsregs.h

@@ -116,6 +116,70 @@
 #define CP1_REVISION   		$0
 #define CP1_STATUS     		$31
 
+/*
+ * FPU Status Register Values
+ */
+/*
+ * Status Register Values
+ */
+
+#define FPU_CSR_FLUSH   0x01000000      /* flush denormalised results to 0 */
+#define FPU_CSR_COND    0x00800000      /* $fcc0 */
+#define FPU_CSR_COND0   0x00800000      /* $fcc0 */
+#define FPU_CSR_COND1   0x02000000      /* $fcc1 */
+#define FPU_CSR_COND2   0x04000000      /* $fcc2 */
+#define FPU_CSR_COND3   0x08000000      /* $fcc3 */
+#define FPU_CSR_COND4   0x10000000      /* $fcc4 */
+#define FPU_CSR_COND5   0x20000000      /* $fcc5 */
+#define FPU_CSR_COND6   0x40000000      /* $fcc6 */
+#define FPU_CSR_COND7   0x80000000      /* $fcc7 */
+
+
+/* FS/FO/FN */
+#define FPU_CSR_FS      0x01000000
+#define FPU_CSR_FO      0x00400000
+#define FPU_CSR_FN      0x00200000
+
+/*
+ * Bits 18 - 20 of the FPU Status Register will be read as 0,
+ * and should be written as zero.
+ */
+#define FPU_CSR_RSVD	0x001c0000
+
+/*
+ * X the exception cause indicator
+ * E the exception enable
+ * S the sticky/flag bit
+*/
+#define FPU_CSR_ALL_X   0x0003f000
+#define FPU_CSR_UNI_X   0x00020000
+#define FPU_CSR_INV_X   0x00010000
+#define FPU_CSR_DIV_X   0x00008000
+#define FPU_CSR_OVF_X   0x00004000
+#define FPU_CSR_UDF_X   0x00002000
+#define FPU_CSR_INE_X   0x00001000
+
+#define FPU_CSR_ALL_E   0x00000f80
+#define FPU_CSR_INV_E   0x00000800
+#define FPU_CSR_DIV_E   0x00000400
+#define FPU_CSR_OVF_E   0x00000200
+#define FPU_CSR_UDF_E   0x00000100
+#define FPU_CSR_INE_E   0x00000080
+
+#define FPU_CSR_ALL_S   0x0000007c
+#define FPU_CSR_INV_S   0x00000040
+#define FPU_CSR_DIV_S   0x00000020
+#define FPU_CSR_OVF_S   0x00000010
+#define FPU_CSR_UDF_S   0x00000008
+#define FPU_CSR_INE_S   0x00000004
+
+/* Bits 0 and 1 of FPU Status Register specify the rounding mode */
+#define FPU_CSR_RM	0x00000003
+#define FPU_CSR_RN      0x0     /* nearest */
+#define FPU_CSR_RZ      0x1     /* towards zero */
+#define FPU_CSR_RU      0x2     /* towards +Infinity */
+#define FPU_CSR_RD      0x3     /* towards -Infinity */
+
 
 /*
  * R4x00 interrupt enable / cause bits
@@ -610,6 +674,32 @@ do {									\
 #define write_c0_config3(val)	__write_32bit_c0_register($16, 3, val)
 
 
+/*
+ * Macros to access the floating point coprocessor control registers
+ */
+#define read_32bit_cp1_register(source)                         \
+({ int __res;                                                   \
+	__asm__ __volatile__(                                   \
+	".set\tpush\n\t"					\
+	".set\treorder\n\t"					\
+	/* gas fails to assemble cfc1 for some archs (octeon).*/ \
+	".set\tmips1\n\t"					\
+        "cfc1\t%0,"STR(source)"\n\t"                            \
+	".set\tpop"						\
+        : "=r" (__res));                                        \
+        __res;})
+#define write_32bit_cp1_register(register, value)   \
+do {                                        \
+    __asm__ __volatile__(                   \
+        "ctc1\t%z0, "STR(register)"\n\t"      \
+        : : "Jr" ((unsigned int)(value)));  \
+} while (0)
+        
+#define read_c1_status()            read_32bit_cp1_register(CP1_STATUS)
+#define read_c1_revision()          read_32bit_cp1_register(CP1_REVISION);
+#define write_c1_status(val)        write_32bit_cp1_register(CP1_STATUS, val)
+
+
 #endif /* end of __ASSEMBLY__ */
 
 #endif /* end of __MIPSREGS_H__ */

libcpu/mips/loongson_1c/context_gcc.S

@@ -16,6 +16,7 @@
 
 #include "../common/mips.inc"
 #include "../common/stackframe.h"
+#include "stackframe_fpu.h"
 
     .section ".text", "ax"
     .set noreorder
@@ -56,10 +57,12 @@ rt_hw_interrupt_enable:
 rt_hw_context_switch:
     mtc0    ra, CP0_EPC
     SAVE_ALL
+    SAVE_FPU
 
     sw      sp, 0(a0)       /* store sp in preempted tasks TCB */
     lw      sp, 0(a1)       /* get new task stack pointer */
 
+    RESTORE_FPU
     RESTORE_ALL_AND_RET
 
 /*
@@ -70,6 +73,7 @@ rt_hw_context_switch:
 rt_hw_context_switch_to:
     lw      sp, 0(a0)       /* get new task stack pointer */
 
+    RESTORE_FPU
     RESTORE_ALL_AND_RET
 
 /*
@@ -103,6 +107,7 @@ _reswitch:
     .globl mips_irq_handle
 mips_irq_handle:
     SAVE_ALL
+    SAVE_FPU
 
     mfc0    t0, CP0_CAUSE
     and     t1, t0, 0xff
@@ -151,6 +156,7 @@ mips_irq_handle:
     nop
 
 spurious_interrupt:
+    RESTORE_FPU
     RESTORE_ALL_AND_RET
 
     .set reorder

libcpu/mips/loongson_1c/stackframe_fpu.h

+/*
+ * ls1c FPU's stackframe
+ * 最开始本想，将代码加入到stackframe.h中的SAVE_ALL, RESTORE_ALL和RESTORE_ALL_AND_RET中，
+ * 但考虑到源文件"stackframe.h"位于目录"libcpu\mips\common"内，怕影响到其它mips cpu
+ * 所以，另外新建本源文件
+ */
+#ifndef __OPENLOONGSON_STACKFRAME_FPU_H
+#define __OPENLOONGSON_STACKFRAME_FPU_H
+
+
+#include "../common/asm.h"
+#include "../common/mipsregs.h"
+#include "../common/stackframe.h"
+
+
+
+#define PT_FPU_R0               (0)
+#define PT_FPU_R2               ((PT_FPU_R0) + 2*LONGSIZE)
+#define PT_FPU_R4               ((PT_FPU_R2) + 2*LONGSIZE)
+#define PT_FPU_R6               ((PT_FPU_R4) + 2*LONGSIZE)
+#define PT_FPU_R8               ((PT_FPU_R6) + 2*LONGSIZE)
+#define PT_FPU_R10              ((PT_FPU_R8) + 2*LONGSIZE)
+#define PT_FPU_R12              ((PT_FPU_R10) + 2*LONGSIZE)
+#define PT_FPU_R14              ((PT_FPU_R12) + 2*LONGSIZE)
+#define PT_FPU_R16              ((PT_FPU_R14) + 2*LONGSIZE)
+#define PT_FPU_R18              ((PT_FPU_R16) + 2*LONGSIZE)
+#define PT_FPU_R20              ((PT_FPU_R18) + 2*LONGSIZE)
+#define PT_FPU_R22              ((PT_FPU_R20) + 2*LONGSIZE)
+#define PT_FPU_R24              ((PT_FPU_R22) + 2*LONGSIZE)
+#define PT_FPU_R26              ((PT_FPU_R24) + 2*LONGSIZE)
+#define PT_FPU_R28              ((PT_FPU_R26) + 2*LONGSIZE)
+#define PT_FPU_R30              ((PT_FPU_R28) + 2*LONGSIZE)
+
+#define PT_FPU_SIZE             ((((PT_FPU_R30) + 2*LONGSIZE) + (2*PTRSIZE-1)) & ~(2*PTRSIZE-1))
+
+
+    .macro SAVE_FPU
+    .set push
+    .set noreorder
+    move k1, sp                     /* 保存现场 */
+    and k0, k1, 0xFFFFFFF8          /* 8字节对齐 */    
+    PTR_SUBU sp, k0, PT_FPU_SIZE    /* 计算栈底 */
+    s.d $f0, PT_FPU_R0(sp)
+    s.d $f2, PT_FPU_R2(sp)
+    s.d $f4, PT_FPU_R4(sp)
+    s.d $f6, PT_FPU_R6(sp)
+    s.d $f8, PT_FPU_R8(sp)
+    s.d $f10, PT_FPU_R10(sp)
+    s.d $f12, PT_FPU_R12(sp)
+    s.d $f14, PT_FPU_R14(sp)
+    s.d $f16, PT_FPU_R16(sp)
+    s.d $f18, PT_FPU_R18(sp)
+    s.d $f20, PT_FPU_R20(sp)
+    s.d $f22, PT_FPU_R22(sp)
+    s.d $f24, PT_FPU_R24(sp)
+    s.d $f26, PT_FPU_R26(sp)
+    s.d $f28, PT_FPU_R28(sp)
+    s.d $f30, PT_FPU_R30(sp)
+    move sp, k1                     /* 恢复现场 */
+    .set reorder
+    .set pop
+    .endm
+
+
+    .macro RESTORE_FPU
+    .set push
+    .set noreorder
+    move k1, sp                     /* 保存现场 */
+    and k0, k1, 0xFFFFFFF8          /* 8字节对齐 */
+    PTR_SUBU sp, k0, PT_FPU_SIZE    /* 计算栈底*/
+    l.d $f0, PT_FPU_R0(sp)
+    l.d $f2, PT_FPU_R2(sp)
+    l.d $f4, PT_FPU_R4(sp)
+    l.d $f6, PT_FPU_R6(sp)
+    l.d $f8, PT_FPU_R8(sp)
+    l.d $f10, PT_FPU_R10(sp)
+    l.d $f12, PT_FPU_R12(sp)
+    l.d $f14, PT_FPU_R14(sp)
+    l.d $f16, PT_FPU_R16(sp)
+    l.d $f18, PT_FPU_R18(sp)
+    l.d $f20, PT_FPU_R20(sp)
+    l.d $f22, PT_FPU_R22(sp)
+    l.d $f24, PT_FPU_R24(sp)
+    l.d $f26, PT_FPU_R26(sp)
+    l.d $f28, PT_FPU_R28(sp)
+    l.d $f30, PT_FPU_R30(sp)
+    move sp, k1                     /* 恢复现场 */
+    .set reorder
+    .set pop
+    .endm
+
+
+#endif
+