Support FPU - RISC-V architecture (GCC)

Signed-off-by: Emmanuel Puerto <emmanuel.puerto@sifive.com>
This commit is contained in:
Emmanuel Puerto 2020-08-26 09:49:27 +02:00
parent 2167df2446
commit 102df3fa08

View file

@ -82,8 +82,29 @@
#define portWORD_SIZE (__riscv_xlen / 8)
/* Number of FPU register */
/* FPU is not yet supported so PORT_FPU_REGISTER = 0 */
#define portasmFPU_CONTEXT_SIZE 0
#ifdef __riscv_fdiv
#define MSTATUS_FS 0x00006000 /* Floating-point Status */
#define MSTATUS_FS_OFF 0x00000000
#define MSTATUS_FS_INITIAL 0x00002000
#define MSTATUS_FS_CLEAN 0x00004000
#define MSTATUS_FS_DIRTY 0x00006000
#if __riscv_flen == 32
#define store_fpu fsw
#define load_fpu flw
#endif /* __riscv_flen == 32 */
#if __riscv_flen == 64
#define store_fpu fsd
#define load_fpu fld
#endif /* __riscv_flen == 64 */
#define portasmFPU_CONTEXT_SIZE (32)
#define portFPUWORD_SIZE (__riscv_flen / 8)
#else
#define portasmFPU_CONTEXT_SIZE (0)
#define portFPUWORD_SIZE (0)
#endif /* __riscv_fdiv */
#include "freertos_risc_v_chip_specific_extensions.h"
@ -138,10 +159,12 @@ definitions. */
#define PORT_CONTEXT_mepcOFFSET (PORT_CONTEXT_mepcIDX * portWORD_SIZE)
#define PORT_CONTEXT_mstatusOFFSET (PORT_CONTEXT_mstatusIDX * portWORD_SIZE)
#define PORT_CONTEXT_rufOFFSET (PORT_CONTEXT_rufIDX * portWORD_SIZE)
#define PORT_CONTEXT_fpuOFFSET(X) ((X) * portFPUWORD_SIZE)
/* total size of the structure usable in ASM. */
#define portasmREGISTER_CONTEXT_WORDSIZE ((portasmLAST_BASE_REGS) * (portWORD_SIZE))
#define portasmADDITIONAL_CONTEXT_WORDSIZE ((portasmADDITIONAL_CONTEXT_SIZE) * (portWORD_SIZE))
#define portasmFPU_CONTEXT_WORDSIZE ((portasmFPU_CONTEXT_SIZE) * (portFPUWORD_SIZE))
.global xPortStartFirstTask
.global freertos_risc_v_trap_handler
@ -158,6 +181,131 @@ definitions. */
.extern portHANDLE_INTERRUPT
.extern portHANDLE_EXCEPTION
/*-----------------------------------------------------------*/
#ifdef __riscv_fdiv
.macro portSAVE_FpuReg
/* get FS field from mstatus */
li t0, MSTATUS_FS
csrr t1, mstatus
and t0, t1, t0
li t2, MSTATUS_FS_DIRTY
bne t2, t0, 1f
/* FS == dirty */
/* Make room for the additional FPU registers. */
addi sp, sp, -portasmFPU_CONTEXT_WORDSIZE
store_fpu f0, PORT_CONTEXT_fpuOFFSET(0)(sp) /* f0(ft0) FP temporary register */
store_fpu f1, PORT_CONTEXT_fpuOFFSET(1)(sp) /* f1(ft1) FP temporary register */
store_fpu f2, PORT_CONTEXT_fpuOFFSET(2)(sp) /* f2(ft2) FP temporary register */
store_fpu f3, PORT_CONTEXT_fpuOFFSET(3)(sp) /* f3(ft3) FP temporary register */
store_fpu f4, PORT_CONTEXT_fpuOFFSET(4)(sp) /* f4(ft4) FP temporary register */
store_fpu f5, PORT_CONTEXT_fpuOFFSET(5)(sp) /* f5(ft5) FP temporary register */
store_fpu f6, PORT_CONTEXT_fpuOFFSET(6)(sp) /* f6(ft6) FP temporary register */
store_fpu f7, PORT_CONTEXT_fpuOFFSET(7)(sp) /* f7(ft7) FP temporary register */
store_fpu f8, PORT_CONTEXT_fpuOFFSET(8)(sp) /* f8(fs0) FP Saved register */
store_fpu f9, PORT_CONTEXT_fpuOFFSET(9)(sp) /* f9(fs0) FP Saved register */
store_fpu f10, PORT_CONTEXT_fpuOFFSET(10)(sp) /* f10(fa0) FP arguments/return values register */
store_fpu f11, PORT_CONTEXT_fpuOFFSET(11)(sp) /* f11(fa1) FP arguments/return values register */
store_fpu f12, PORT_CONTEXT_fpuOFFSET(12)(sp) /* f12(fa2) FP arguments register */
store_fpu f13, PORT_CONTEXT_fpuOFFSET(13)(sp) /* f13(fa3) FP arguments register */
store_fpu f14, PORT_CONTEXT_fpuOFFSET(14)(sp) /* f14(fa4) FP arguments register */
store_fpu f15, PORT_CONTEXT_fpuOFFSET(15)(sp) /* f15(fa5) FP arguments register */
store_fpu f16, PORT_CONTEXT_fpuOFFSET(16)(sp) /* f16(fa6) FP arguments register */
store_fpu f17, PORT_CONTEXT_fpuOFFSET(17)(sp) /* f17(fa7) FP arguments register */
store_fpu f18, PORT_CONTEXT_fpuOFFSET(18)(sp) /* f18(fs2) FP Saved register */
store_fpu f19, PORT_CONTEXT_fpuOFFSET(19)(sp) /* f19(fs3) FP Saved register */
store_fpu f20, PORT_CONTEXT_fpuOFFSET(20)(sp) /* f20(fs4) FP Saved register */
store_fpu f21, PORT_CONTEXT_fpuOFFSET(21)(sp) /* f21(fs5) FP Saved register */
store_fpu f22, PORT_CONTEXT_fpuOFFSET(22)(sp) /* f22(fs6) FP Saved register */
store_fpu f23, PORT_CONTEXT_fpuOFFSET(23)(sp) /* f23(fs7) FP Saved register */
store_fpu f24, PORT_CONTEXT_fpuOFFSET(24)(sp) /* f24(fs8) FP Saved register */
store_fpu f25, PORT_CONTEXT_fpuOFFSET(25)(sp) /* f25(fs9) FP Saved register */
store_fpu f26, PORT_CONTEXT_fpuOFFSET(26)(sp) /* f26(fs10) FP Saved register */
store_fpu f27, PORT_CONTEXT_fpuOFFSET(27)(sp) /* f27(fs11) FP Saved register */
store_fpu f28, PORT_CONTEXT_fpuOFFSET(28)(sp) /* f28(ft8) FP temporary register */
store_fpu f29, PORT_CONTEXT_fpuOFFSET(29)(sp) /* f29(ft9) FP temporary register */
store_fpu f30, PORT_CONTEXT_fpuOFFSET(30)(sp) /* f30(ft10) FP temporary register */
store_fpu f31, PORT_CONTEXT_fpuOFFSET(31)(sp) /* f31(ft11) FP temporary register */
/* must set FS to clean */
csrc mstatus, t0
li t1, MSTATUS_FS_CLEAN
csrs mstatus, t1
1:
.endm
#else
.macro portSAVE_FpuReg
/* No fpu registers to save, so this macro does nothing. */
.endm
#endif /* __riscv_fdiv */
/*-----------------------------------------------------------*/
#ifdef __riscv_fdiv
.macro portRESTORE_FpuReg
/* get FS field from mstatus */
li t0, MSTATUS_FS
csrr t1, mstatus
and t0, t1, t0
li t2, MSTATUS_FS_OFF
beq t2, t0, 1f
/* FS != off */
csrs mstatus, t0
/* Remove space added for additional fpu registers. */
addi sp, sp, portasmFPU_CONTEXT_WORDSIZE
load_fpu f0, PORT_CONTEXT_fpuOFFSET(0)(sp) /* f0(ft0) FP temporary register */
load_fpu f1, PORT_CONTEXT_fpuOFFSET(1)(sp) /* f1(ft1) FP temporary register */
load_fpu f2, PORT_CONTEXT_fpuOFFSET(2)(sp) /* f2(ft2) FP temporary register */
load_fpu f3, PORT_CONTEXT_fpuOFFSET(3)(sp) /* f3(ft3) FP temporary register */
load_fpu f4, PORT_CONTEXT_fpuOFFSET(4)(sp) /* f4(ft4) FP temporary register */
load_fpu f5, PORT_CONTEXT_fpuOFFSET(5)(sp) /* f5(ft5) FP temporary register */
load_fpu f6, PORT_CONTEXT_fpuOFFSET(6)(sp) /* f6(ft6) FP temporary register */
load_fpu f7, PORT_CONTEXT_fpuOFFSET(7)(sp) /* f7(ft7) FP temporary register */
load_fpu f8, PORT_CONTEXT_fpuOFFSET(8)(sp) /* f8(fs0) FP Saved register */
load_fpu f9, PORT_CONTEXT_fpuOFFSET(9)(sp) /* f9(fs0) FP Saved register */
load_fpu f10, PORT_CONTEXT_fpuOFFSET(10)(sp) /* f10(fa0) FP arguments/return values register */
load_fpu f11, PORT_CONTEXT_fpuOFFSET(11)(sp) /* f11(fa1) FP arguments/return values register */
load_fpu f12, PORT_CONTEXT_fpuOFFSET(12)(sp) /* f12(fa2) FP arguments register */
load_fpu f13, PORT_CONTEXT_fpuOFFSET(13)(sp) /* f13(fa3) FP arguments register */
load_fpu f14, PORT_CONTEXT_fpuOFFSET(14)(sp) /* f14(fa4) FP arguments register */
load_fpu f15, PORT_CONTEXT_fpuOFFSET(15)(sp) /* f15(fa5) FP arguments register */
load_fpu f16, PORT_CONTEXT_fpuOFFSET(16)(sp) /* f16(fa6) FP arguments register */
load_fpu f17, PORT_CONTEXT_fpuOFFSET(17)(sp) /* f17(fa7) FP arguments register */
load_fpu f18, PORT_CONTEXT_fpuOFFSET(18)(sp) /* f18(fs2) FP Saved register */
load_fpu f19, PORT_CONTEXT_fpuOFFSET(19)(sp) /* f19(fs3) FP Saved register */
load_fpu f20, PORT_CONTEXT_fpuOFFSET(20)(sp) /* f20(fs4) FP Saved register */
load_fpu f21, PORT_CONTEXT_fpuOFFSET(21)(sp) /* f21(fs5) FP Saved register */
load_fpu f22, PORT_CONTEXT_fpuOFFSET(22)(sp) /* f22(fs6) FP Saved register */
load_fpu f23, PORT_CONTEXT_fpuOFFSET(23)(sp) /* f23(fs7) FP Saved register */
load_fpu f24, PORT_CONTEXT_fpuOFFSET(24)(sp) /* f24(fs8) FP Saved register */
load_fpu f25, PORT_CONTEXT_fpuOFFSET(25)(sp) /* f25(fs9) FP Saved register */
load_fpu f26, PORT_CONTEXT_fpuOFFSET(26)(sp) /* f26(fs10) FP Saved register */
load_fpu f27, PORT_CONTEXT_fpuOFFSET(27)(sp) /* f27(fs11) FP Saved register */
load_fpu f28, PORT_CONTEXT_fpuOFFSET(28)(sp) /* f28(ft8) FP temporary register */
load_fpu f29, PORT_CONTEXT_fpuOFFSET(29)(sp) /* f29(ft9) FP temporary register */
load_fpu f30, PORT_CONTEXT_fpuOFFSET(30)(sp) /* f30(ft10) FP temporary register */
load_fpu f31, PORT_CONTEXT_fpuOFFSET(31)(sp) /* f31(ft11) FP temporary register */
/* must set FS to clean */
csrc mstatus, t0
li t1, MSTATUS_FS_CLEAN
csrs mstatus, t1
1:
.endm
#else
.macro portRESTORE_FpuReg
/* No fpu registers to restore, so this macro does nothing. */
.endm
#endif /* __riscv_fdiv */
/*-----------------------------------------------------------*/
.macro portSAVE_BaseReg
/* Make room for the registers. */
@ -302,9 +450,12 @@ is_exception:
store_x t0, PORT_CONTEXT_xOFFSET(2)(sp)
/* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
portasmSAVE_ADDITIONAL_REGISTERS
/* Save any fpu registers */
portSAVE_FpuReg
/* Execption is treated by external function */
jal portHANDLE_EXCEPTION
/* in case that the go back from exception, restore registers */
portRESTORE_FpuReg
portasmRESTORE_ADDITIONAL_REGISTERS
portRESTORE_BaseReg
load_x x2, PORT_CONTEXT_xOFFSET(2)(sp)
@ -326,6 +477,8 @@ ecall_yield:
/* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
portasmSAVE_ADDITIONAL_REGISTERS
/* Save any fpu registers */
portSAVE_FpuReg
/* Load pxCurrentTCB and update first TCB member(pxTopOfStack) with sp. */
load_x s0, pxCurrentTCB
@ -351,6 +504,8 @@ handle_interrupt:
/* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
portasmSAVE_ADDITIONAL_REGISTERS
/* Save any fpu registers */
portSAVE_FpuReg
/* Load pxCurrentTCB and update first TCB member(pxTopOfStack) with sp. */
load_x s0, pxCurrentTCB
@ -435,6 +590,7 @@ end_trap_handler:
store_x t1, 0( s0 ) /* Write sp saved value to first TCB member. */
/* restore registers */
portRESTORE_FpuReg
portasmRESTORE_ADDITIONAL_REGISTERS
portRESTORE_BaseReg
load_x x2, PORT_CONTEXT_xOFFSET(2)(sp)
@ -454,6 +610,20 @@ xPortStartFirstTask:
csrw mtvec, t0
#endif /* ( portasmHAS_SIFIVE_CLINT != 0 ) */
#ifdef __riscv_fdiv
/* we put the FPU in initial state */
csrr t0, misa /* Get misa */
li t1, 0x10028 /* 0x10028 = Q,F,D Quad, Single or Double precission floating point */
and t0, t0, t1
beqz t0, 1f /* check if Q,F or D is present into misa */
csrr t0, mstatus /* Floating point unit is present so need to put it into initial state */
lui t1, 0x1 /* t1 = 0x1 << 12 */
or t0, t0, t1
csrw mstatus, t0 /* Set FS to initial state */
csrwi fcsr, 0 /* Clear Floating-point Control and Status Register */
1:
#endif /* __riscv_fdiv */
/** Set all register to the FirstTask context */
load_x t2, pxCurrentTCB /* Load pxCurrentTCB. */
load_x sp, 0( t2 ) /* Read sp from first TCB member. */
@ -471,6 +641,7 @@ xPortStartFirstTask:
csrs mie, t0
#endif /* ( portasmHAS_MTIME != 0 ) */
portRESTORE_FpuReg
portasmRESTORE_ADDITIONAL_REGISTERS
portRESTORE_BaseReg
@ -627,6 +798,20 @@ chip_specific_stack_frame: /* First add any chip specific registers to the st
j chip_specific_stack_frame /* Until no more chip specific registers. */
1:
#ifdef __riscv_fdiv
/* Make room for the fpu registers. */
/* Here we use the memory space needed for all fpu registers instead of using the number of fpu registers */
/* Thanks to it we usually manage any xxbits core with yybits fpu */
addi t0, x0, portasmFPU_CONTEXT_WORDSIZE
fpu_specific_stack_frame:
beq t0, x0, 1f /* No more space is needed. */
addi t2, t2, -portWORD_SIZE
store_x x0, 0(t2) /* Give an initial value of zero. */
addi t0, t0, -portWORD_SIZE /* Decrement the count space remaining. */
j fpu_specific_stack_frame /* Until no more space is needed. */
1:
#endif /* __riscv_fdiv */
mv a0, t2
ret
.endfunc