RISCV Add FPU context save (#1250)
* port: riscv: Split the number of registers and the size of the context
* port: riscv: Create some macros for the FPU context
* port: riscv: Add a couple of macros that store fpu context
* port: riscv: Update the stack init function to include the fpu context size
* port: riscv: Add a chip_specific_extensions file that includes the F extension
* Update dictionary to include some risc-v instructions
* port: riscv: Fix a few typos
* port: riscv: Apply @aggarg's sugestions
diff --git a/.github/.cSpellWords.txt b/.github/.cSpellWords.txt
index 3582741..27fb0fc 100644
--- a/.github/.cSpellWords.txt
+++ b/.github/.cSpellWords.txt
@@ -23,6 +23,7 @@
ALMIEN
ALMV
ANDC
+andi
ANDCCR
APIC
APROCFREQ
@@ -47,6 +48,7 @@
BCPC
beevt
BEEVT
+beqz
BERR
bfextu
Biagioni
@@ -298,6 +300,7 @@
FCMD
fcolor
FCSE
+fcsr
fdiagnostics
fdiv
FDIV
diff --git a/portable/GCC/RISC-V/chip_specific_extensions/Pulpino_Vega_RV32M1RM/freertos_risc_v_chip_specific_extensions.h b/portable/GCC/RISC-V/chip_specific_extensions/Pulpino_Vega_RV32M1RM/freertos_risc_v_chip_specific_extensions.h
index 4d8a5fb..c10869e 100644
--- a/portable/GCC/RISC-V/chip_specific_extensions/Pulpino_Vega_RV32M1RM/freertos_risc_v_chip_specific_extensions.h
+++ b/portable/GCC/RISC-V/chip_specific_extensions/Pulpino_Vega_RV32M1RM/freertos_risc_v_chip_specific_extensions.h
@@ -80,22 +80,22 @@
csrr t3, lpstart1
csrr t4, lpend1
csrr t5, lpcount1
-sw t0, 1 * portWORD_SIZE( sp )
-sw t1, 2 * portWORD_SIZE( sp )
-sw t2, 3 * portWORD_SIZE( sp )
-sw t3, 4 * portWORD_SIZE( sp )
-sw t4, 5 * portWORD_SIZE( sp )
-sw t5, 6 * portWORD_SIZE( sp )
+sw t0, 2 * portWORD_SIZE( sp )
+sw t1, 3 * portWORD_SIZE( sp )
+sw t2, 4 * portWORD_SIZE( sp )
+sw t3, 5 * portWORD_SIZE( sp )
+sw t4, 6 * portWORD_SIZE( sp )
+sw t5, 7 * portWORD_SIZE( sp )
.endm
/* Restore the additional registers found on the Pulpino. */
.macro portasmRESTORE_ADDITIONAL_REGISTERS
-lw t0, 1 * portWORD_SIZE( sp ) /* Load additional registers into accessible temporary registers. */
-lw t1, 2 * portWORD_SIZE( sp )
-lw t2, 3 * portWORD_SIZE( sp )
-lw t3, 4 * portWORD_SIZE( sp )
-lw t4, 5 * portWORD_SIZE( sp )
-lw t5, 6 * portWORD_SIZE( sp )
+lw t0, 2 * portWORD_SIZE( sp ) /* Load additional registers into accessible temporary registers. */
+lw t1, 3 * portWORD_SIZE( sp )
+lw t2, 4 * portWORD_SIZE( sp )
+lw t3, 5 * portWORD_SIZE( sp )
+lw t4, 6 * portWORD_SIZE( sp )
+lw t5, 7 * portWORD_SIZE( sp )
csrw lpstart0, t0
csrw lpend0, t1
csrw lpcount0, t2
diff --git a/portable/GCC/RISC-V/portASM.S b/portable/GCC/RISC-V/portASM.S
index 99613ad..1fe50f6 100644
--- a/portable/GCC/RISC-V/portASM.S
+++ b/portable/GCC/RISC-V/portASM.S
@@ -162,7 +162,6 @@
* where the global and thread pointers are currently assumed to be constant so
* are not saved:
*
- * mstatus
* xCriticalNesting
* x31
* x30
@@ -192,18 +191,12 @@
* x6
* x5
* portTASK_RETURN_ADDRESS
+ * [FPU registers (when enabled/available) go here]
* [chip specific registers go here]
+ * mstatus
* pxCode
*/
pxPortInitialiseStack:
- csrr t0, mstatus /* Obtain current mstatus value. */
- andi t0, t0, ~0x8 /* Ensure interrupts are disabled when the stack is restored within an ISR. Required when a task is created after the schedulre has been started, otherwise interrupts would be disabled anyway. */
- addi t1, x0, 0x188 /* Generate the value 0x1880, which are the MPIE and MPP bits to set in mstatus. */
- slli t1, t1, 4
- or t0, t0, t1 /* Set MPIE and MPP bits in mstatus value. */
-
- addi a0, a0, -portWORD_SIZE
- store_x t0, 0(a0) /* mstatus onto the stack. */
addi a0, a0, -portWORD_SIZE /* Space for critical nesting count. */
store_x x0, 0(a0) /* Critical nesting count starts at 0 for every task. */
@@ -212,10 +205,12 @@
#else
addi a0, a0, -(22 * portWORD_SIZE) /* Space for registers x10-x31. */
#endif
- store_x a2, 0(a0) /* Task parameters (pvParameters parameter) goes into register X10/a0 on the stack. */
- addi a0, a0, -(6 * portWORD_SIZE) /* Space for registers x5-x9 + taskReturnAddress. */
+ store_x a2, 0(a0) /* Task parameters (pvParameters parameter) goes into register x10/a0 on the stack. */
+
+ addi a0, a0, -(6 * portWORD_SIZE) /* Space for registers x5-x9 + taskReturnAddress (register x1). */
load_x t0, xTaskReturnAddress
store_x t0, 0(a0) /* Return address onto the stack. */
+
addi t0, x0, portasmADDITIONAL_CONTEXT_SIZE /* The number of chip specific additional registers. */
chip_specific_stack_frame: /* First add any chip specific registers to the stack frame being created. */
beq t0, x0, 1f /* No more chip specific registers to save. */
@@ -224,6 +219,23 @@
addi t0, t0, -1 /* Decrement the count of chip specific registers remaining. */
j chip_specific_stack_frame /* Until no more chip specific registers. */
1:
+ csrr t0, mstatus /* Obtain current mstatus value. */
+ andi t0, t0, ~0x8 /* Ensure interrupts are disabled when the stack is restored within an ISR. Required when a task is created after the scheduler has been started, otherwise interrupts would be disabled anyway. */
+ addi t1, x0, 0x188 /* Generate the value 0x1880, which are the MPIE=1 and MPP=M_Mode in mstatus. */
+ slli t1, t1, 4
+ or t0, t0, t1 /* Set MPIE and MPP bits in mstatus value. */
+
+#if( configENABLE_FPU == 1 )
+ /* Mark the FPU as clean in the mstatus value. */
+ li t1, ~MSTATUS_FS_MASK
+ and t0, t0, t1
+ li t1, MSTATUS_FS_CLEAN
+ or t0, t0, t1
+#endif
+
+ addi a0, a0, -portWORD_SIZE
+ store_x t0, 0(a0) /* mstatus onto the stack. */
+
addi a0, a0, -portWORD_SIZE
store_x a1, 0(a0) /* mret value (pxCode parameter) onto the stack. */
ret
@@ -235,46 +247,46 @@
load_x x1, 0( sp ) /* Note for starting the scheduler the exception return address is used as the function return address. */
+ load_x x5, 1 * portWORD_SIZE( sp ) /* Initial mstatus into x5 (t0). */
+ addi x5, x5, 0x08 /* Set MIE bit so the first task starts with interrupts enabled - required as returns with ret not eret. */
+ csrw mstatus, x5 /* Interrupts enabled from here! */
+
portasmRESTORE_ADDITIONAL_REGISTERS /* Defined in freertos_risc_v_chip_specific_extensions.h to restore any registers unique to the RISC-V implementation. */
- load_x x7, 4 * portWORD_SIZE( sp ) /* t2 */
- load_x x8, 5 * portWORD_SIZE( sp ) /* s0/fp */
- load_x x9, 6 * portWORD_SIZE( sp ) /* s1 */
- load_x x10, 7 * portWORD_SIZE( sp ) /* a0 */
- load_x x11, 8 * portWORD_SIZE( sp ) /* a1 */
- load_x x12, 9 * portWORD_SIZE( sp ) /* a2 */
- load_x x13, 10 * portWORD_SIZE( sp ) /* a3 */
- load_x x14, 11 * portWORD_SIZE( sp ) /* a4 */
- load_x x15, 12 * portWORD_SIZE( sp ) /* a5 */
+ load_x x7, 5 * portWORD_SIZE( sp ) /* t2 */
+ load_x x8, 6 * portWORD_SIZE( sp ) /* s0/fp */
+ load_x x9, 7 * portWORD_SIZE( sp ) /* s1 */
+ load_x x10, 8 * portWORD_SIZE( sp ) /* a0 */
+ load_x x11, 9 * portWORD_SIZE( sp ) /* a1 */
+ load_x x12, 10 * portWORD_SIZE( sp ) /* a2 */
+ load_x x13, 11 * portWORD_SIZE( sp ) /* a3 */
+ load_x x14, 12 * portWORD_SIZE( sp ) /* a4 */
+ load_x x15, 13 * portWORD_SIZE( sp ) /* a5 */
#ifndef __riscv_32e
- load_x x16, 13 * portWORD_SIZE( sp ) /* a6 */
- load_x x17, 14 * portWORD_SIZE( sp ) /* a7 */
- load_x x18, 15 * portWORD_SIZE( sp ) /* s2 */
- load_x x19, 16 * portWORD_SIZE( sp ) /* s3 */
- load_x x20, 17 * portWORD_SIZE( sp ) /* s4 */
- load_x x21, 18 * portWORD_SIZE( sp ) /* s5 */
- load_x x22, 19 * portWORD_SIZE( sp ) /* s6 */
- load_x x23, 20 * portWORD_SIZE( sp ) /* s7 */
- load_x x24, 21 * portWORD_SIZE( sp ) /* s8 */
- load_x x25, 22 * portWORD_SIZE( sp ) /* s9 */
- load_x x26, 23 * portWORD_SIZE( sp ) /* s10 */
- load_x x27, 24 * portWORD_SIZE( sp ) /* s11 */
- load_x x28, 25 * portWORD_SIZE( sp ) /* t3 */
- load_x x29, 26 * portWORD_SIZE( sp ) /* t4 */
- load_x x30, 27 * portWORD_SIZE( sp ) /* t5 */
- load_x x31, 28 * portWORD_SIZE( sp ) /* t6 */
+ load_x x16, 14 * portWORD_SIZE( sp ) /* a6 */
+ load_x x17, 15 * portWORD_SIZE( sp ) /* a7 */
+ load_x x18, 16 * portWORD_SIZE( sp ) /* s2 */
+ load_x x19, 17 * portWORD_SIZE( sp ) /* s3 */
+ load_x x20, 18 * portWORD_SIZE( sp ) /* s4 */
+ load_x x21, 19 * portWORD_SIZE( sp ) /* s5 */
+ load_x x22, 20 * portWORD_SIZE( sp ) /* s6 */
+ load_x x23, 21 * portWORD_SIZE( sp ) /* s7 */
+ load_x x24, 22 * portWORD_SIZE( sp ) /* s8 */
+ load_x x25, 23 * portWORD_SIZE( sp ) /* s9 */
+ load_x x26, 24 * portWORD_SIZE( sp ) /* s10 */
+ load_x x27, 25 * portWORD_SIZE( sp ) /* s11 */
+ load_x x28, 26 * portWORD_SIZE( sp ) /* t3 */
+ load_x x29, 27 * portWORD_SIZE( sp ) /* t4 */
+ load_x x30, 28 * portWORD_SIZE( sp ) /* t5 */
+ load_x x31, 29 * portWORD_SIZE( sp ) /* t6 */
#endif
load_x x5, portCRITICAL_NESTING_OFFSET * portWORD_SIZE( sp ) /* Obtain xCriticalNesting value for this task from task's stack. */
load_x x6, pxCriticalNesting /* Load the address of xCriticalNesting into x6. */
store_x x5, 0( x6 ) /* Restore the critical nesting value for this task. */
- load_x x5, portMSTATUS_OFFSET * portWORD_SIZE( sp ) /* Initial mstatus into x5 (t0). */
- addi x5, x5, 0x08 /* Set MIE bit so the first task starts with interrupts enabled - required as returns with ret not eret. */
- csrrw x0, mstatus, x5 /* Interrupts enabled from here! */
-
- load_x x5, 2 * portWORD_SIZE( sp ) /* Initial x5 (t0) value. */
- load_x x6, 3 * portWORD_SIZE( sp ) /* Initial x6 (t1) value. */
+ load_x x5, 3 * portWORD_SIZE( sp ) /* Initial x5 (t0) value. */
+ load_x x6, 4 * portWORD_SIZE( sp ) /* Initial x6 (t1) value. */
addi sp, sp, portCONTEXT_SIZE
ret
diff --git a/portable/GCC/RISC-V/portContext.h b/portable/GCC/RISC-V/portContext.h
index 6baae75..9afe6ee 100644
--- a/portable/GCC/RISC-V/portContext.h
+++ b/portable/GCC/RISC-V/portContext.h
@@ -29,6 +29,10 @@
#ifndef PORTCONTEXT_H
#define PORTCONTEXT_H
+#ifndef configENABLE_FPU
+ #define configENABLE_FPU 0
+#endif
+
#if __riscv_xlen == 64
#define portWORD_SIZE 8
#define store_x sd
@@ -50,65 +54,199 @@
* notes at the top of portASM.S file. */
#ifdef __riscv_32e
#define portCONTEXT_SIZE ( 15 * portWORD_SIZE )
- #define portCRITICAL_NESTING_OFFSET 13
- #define portMSTATUS_OFFSET 14
+ #define portCRITICAL_NESTING_OFFSET 14
#else
#define portCONTEXT_SIZE ( 31 * portWORD_SIZE )
- #define portCRITICAL_NESTING_OFFSET 29
- #define portMSTATUS_OFFSET 30
+ #define portCRITICAL_NESTING_OFFSET 30
#endif
+#if ( configENABLE_FPU == 1 )
+ /* Bit [14:13] in the mstatus encode the status of FPU state which is one of
+ * the following values:
+ * 1. Value: 0, Meaning: Off.
+ * 2. Value: 1, Meaning: Initial.
+ * 3. Value: 2, Meaning: Clean.
+ * 4. Value: 3, Meaning: Dirty.
+ */
+ #define MSTATUS_FS_MASK 0x6000
+ #define MSTATUS_FS_INITIAL 0x2000
+ #define MSTATUS_FS_CLEAN 0x4000
+ #define MSTATUS_FS_DIRTY 0x6000
+ #define MSTATUS_FS_OFFSET 13
+
+ #ifdef __riscv_fdiv
+ #if __riscv_flen == 32
+ #define load_f flw
+ #define store_f fsw
+ #elif __riscv_flen == 64
+ #define load_f fld
+ #define store_f fsd
+ #else
+ #error Assembler did not define __riscv_flen
+ #endif
+
+ #define portFPU_REG_SIZE ( __riscv_flen / 8 )
+ #define portFPU_REG_COUNT 33 /* 32 Floating point registers plus one CSR. */
+ #define portFPU_CONTEXT_SIZE ( portFPU_REG_SIZE * portFPU_REG_COUNT )
+ #else
+ #error configENABLE_FPU must not be set to 1 if the hardwar does not have FPU
+ #endif
+#endif
/*-----------------------------------------------------------*/
.extern pxCurrentTCB
- .extern xISRStackTop
- .extern xCriticalNesting
- .extern pxCriticalNesting
+.extern xISRStackTop
+.extern xCriticalNesting
+.extern pxCriticalNesting
+/*-----------------------------------------------------------*/
+
+ .macro portcontexSAVE_FPU_CONTEXT
+addi sp, sp, -( portFPU_CONTEXT_SIZE )
+/* Store the FPU registers. */
+store_f f0, 2 * portWORD_SIZE( sp )
+store_f f1, 3 * portWORD_SIZE( sp )
+store_f f2, 4 * portWORD_SIZE( sp )
+store_f f3, 5 * portWORD_SIZE( sp )
+store_f f4, 6 * portWORD_SIZE( sp )
+store_f f5, 7 * portWORD_SIZE( sp )
+store_f f6, 8 * portWORD_SIZE( sp )
+store_f f7, 9 * portWORD_SIZE( sp )
+store_f f8, 10 * portWORD_SIZE( sp )
+store_f f9, 11 * portWORD_SIZE( sp )
+store_f f10, 12 * portWORD_SIZE( sp )
+store_f f11, 13 * portWORD_SIZE( sp )
+store_f f12, 14 * portWORD_SIZE( sp )
+store_f f13, 15 * portWORD_SIZE( sp )
+store_f f14, 16 * portWORD_SIZE( sp )
+store_f f15, 17 * portWORD_SIZE( sp )
+store_f f16, 18 * portWORD_SIZE( sp )
+store_f f17, 19 * portWORD_SIZE( sp )
+store_f f18, 20 * portWORD_SIZE( sp )
+store_f f19, 21 * portWORD_SIZE( sp )
+store_f f20, 22 * portWORD_SIZE( sp )
+store_f f21, 23 * portWORD_SIZE( sp )
+store_f f22, 24 * portWORD_SIZE( sp )
+store_f f23, 25 * portWORD_SIZE( sp )
+store_f f24, 26 * portWORD_SIZE( sp )
+store_f f25, 27 * portWORD_SIZE( sp )
+store_f f26, 28 * portWORD_SIZE( sp )
+store_f f27, 29 * portWORD_SIZE( sp )
+store_f f28, 30 * portWORD_SIZE( sp )
+store_f f29, 31 * portWORD_SIZE( sp )
+store_f f30, 32 * portWORD_SIZE( sp )
+store_f f31, 33 * portWORD_SIZE( sp )
+csrr t0, fcsr
+store_x t0, 34 * portWORD_SIZE( sp )
+ .endm
+/*-----------------------------------------------------------*/
+
+ .macro portcontextRESTORE_FPU_CONTEXT
+/* Restore the FPU registers. */
+load_f f0, 2 * portWORD_SIZE( sp )
+load_f f1, 3 * portWORD_SIZE( sp )
+load_f f2, 4 * portWORD_SIZE( sp )
+load_f f3, 5 * portWORD_SIZE( sp )
+load_f f4, 6 * portWORD_SIZE( sp )
+load_f f5, 7 * portWORD_SIZE( sp )
+load_f f6, 8 * portWORD_SIZE( sp )
+load_f f7, 9 * portWORD_SIZE( sp )
+load_f f8, 10 * portWORD_SIZE( sp )
+load_f f9, 11 * portWORD_SIZE( sp )
+load_f f10, 12 * portWORD_SIZE( sp )
+load_f f11, 13 * portWORD_SIZE( sp )
+load_f f12, 14 * portWORD_SIZE( sp )
+load_f f13, 15 * portWORD_SIZE( sp )
+load_f f14, 16 * portWORD_SIZE( sp )
+load_f f15, 17 * portWORD_SIZE( sp )
+load_f f16, 18 * portWORD_SIZE( sp )
+load_f f17, 19 * portWORD_SIZE( sp )
+load_f f18, 20 * portWORD_SIZE( sp )
+load_f f19, 21 * portWORD_SIZE( sp )
+load_f f20, 22 * portWORD_SIZE( sp )
+load_f f21, 23 * portWORD_SIZE( sp )
+load_f f22, 24 * portWORD_SIZE( sp )
+load_f f23, 25 * portWORD_SIZE( sp )
+load_f f24, 26 * portWORD_SIZE( sp )
+load_f f25, 27 * portWORD_SIZE( sp )
+load_f f26, 28 * portWORD_SIZE( sp )
+load_f f27, 29 * portWORD_SIZE( sp )
+load_f f28, 30 * portWORD_SIZE( sp )
+load_f f29, 31 * portWORD_SIZE( sp )
+load_f f30, 32 * portWORD_SIZE( sp )
+load_f f31, 33 * portWORD_SIZE( sp )
+load_x t0, 34 * portWORD_SIZE( sp )
+csrw fcsr, t0
+addi sp, sp, ( portFPU_CONTEXT_SIZE )
+ .endm
/*-----------------------------------------------------------*/
.macro portcontextSAVE_CONTEXT_INTERNAL
addi sp, sp, -portCONTEXT_SIZE
-store_x x1, 1 * portWORD_SIZE( sp )
-store_x x5, 2 * portWORD_SIZE( sp )
-store_x x6, 3 * portWORD_SIZE( sp )
-store_x x7, 4 * portWORD_SIZE( sp )
-store_x x8, 5 * portWORD_SIZE( sp )
-store_x x9, 6 * portWORD_SIZE( sp )
-store_x x10, 7 * portWORD_SIZE( sp )
-store_x x11, 8 * portWORD_SIZE( sp )
-store_x x12, 9 * portWORD_SIZE( sp )
-store_x x13, 10 * portWORD_SIZE( sp )
-store_x x14, 11 * portWORD_SIZE( sp )
-store_x x15, 12 * portWORD_SIZE( sp )
+store_x x1, 2 * portWORD_SIZE( sp )
+store_x x5, 3 * portWORD_SIZE( sp )
+store_x x6, 4 * portWORD_SIZE( sp )
+store_x x7, 5 * portWORD_SIZE( sp )
+store_x x8, 6 * portWORD_SIZE( sp )
+store_x x9, 7 * portWORD_SIZE( sp )
+store_x x10, 8 * portWORD_SIZE( sp )
+store_x x11, 9 * portWORD_SIZE( sp )
+store_x x12, 10 * portWORD_SIZE( sp )
+store_x x13, 11 * portWORD_SIZE( sp )
+store_x x14, 12 * portWORD_SIZE( sp )
+store_x x15, 13 * portWORD_SIZE( sp )
#ifndef __riscv_32e
- store_x x16, 13 * portWORD_SIZE( sp )
- store_x x17, 14 * portWORD_SIZE( sp )
- store_x x18, 15 * portWORD_SIZE( sp )
- store_x x19, 16 * portWORD_SIZE( sp )
- store_x x20, 17 * portWORD_SIZE( sp )
- store_x x21, 18 * portWORD_SIZE( sp )
- store_x x22, 19 * portWORD_SIZE( sp )
- store_x x23, 20 * portWORD_SIZE( sp )
- store_x x24, 21 * portWORD_SIZE( sp )
- store_x x25, 22 * portWORD_SIZE( sp )
- store_x x26, 23 * portWORD_SIZE( sp )
- store_x x27, 24 * portWORD_SIZE( sp )
- store_x x28, 25 * portWORD_SIZE( sp )
- store_x x29, 26 * portWORD_SIZE( sp )
- store_x x30, 27 * portWORD_SIZE( sp )
- store_x x31, 28 * portWORD_SIZE( sp )
+ store_x x16, 14 * portWORD_SIZE( sp )
+ store_x x17, 15 * portWORD_SIZE( sp )
+ store_x x18, 16 * portWORD_SIZE( sp )
+ store_x x19, 17 * portWORD_SIZE( sp )
+ store_x x20, 18 * portWORD_SIZE( sp )
+ store_x x21, 19 * portWORD_SIZE( sp )
+ store_x x22, 20 * portWORD_SIZE( sp )
+ store_x x23, 21 * portWORD_SIZE( sp )
+ store_x x24, 22 * portWORD_SIZE( sp )
+ store_x x25, 23 * portWORD_SIZE( sp )
+ store_x x26, 24 * portWORD_SIZE( sp )
+ store_x x27, 25 * portWORD_SIZE( sp )
+ store_x x28, 26 * portWORD_SIZE( sp )
+ store_x x29, 27 * portWORD_SIZE( sp )
+ store_x x30, 28 * portWORD_SIZE( sp )
+ store_x x31, 29 * portWORD_SIZE( sp )
#endif /* ifndef __riscv_32e */
load_x t0, xCriticalNesting /* Load the value of xCriticalNesting into t0. */
store_x t0, portCRITICAL_NESTING_OFFSET * portWORD_SIZE( sp ) /* Store the critical nesting value to the stack. */
+#if( configENABLE_FPU == 1 )
+ csrr t0, mstatus
+ srl t1, t0, MSTATUS_FS_OFFSET
+ andi t1, t1, 3
+ addi t2, x0, 3
+ bne t1, t2, 1f /* If FPU status is not dirty, do not save FPU registers. */
-csrr t0, mstatus /* Required for MPIE bit. */
-store_x t0, portMSTATUS_OFFSET * portWORD_SIZE( sp )
-
+ portcontexSAVE_FPU_CONTEXT
+1:
+#endif
portasmSAVE_ADDITIONAL_REGISTERS /* Defined in freertos_risc_v_chip_specific_extensions.h to save any registers unique to the RISC-V implementation. */
+csrr t0, mstatus
+store_x t0, 1 * portWORD_SIZE( sp )
+
+#if( configENABLE_FPU == 1 )
+ /* Mark the FPU as clean, if it was dirty and we saved FPU registers. */
+ srl t1, t0, MSTATUS_FS_OFFSET
+ andi t1, t1, 3
+ addi t2, x0, 3
+ bne t1, t2, 2f
+
+ li t1, ~MSTATUS_FS_MASK
+ and t0, t0, t1
+ li t1, MSTATUS_FS_CLEAN
+ or t0, t0, t1
+ csrw mstatus, t0
+2:
+#endif
+
load_x t0, pxCurrentTCB /* Load pxCurrentTCB. */
store_x sp, 0 ( t0 ) /* Write sp to first TCB member. */
@@ -142,46 +280,57 @@
load_x t0, 0 ( sp )
csrw mepc, t0
+/* Restore mstatus register. */
+load_x t0, 1 * portWORD_SIZE( sp )
+csrw mstatus, t0
+
/* Defined in freertos_risc_v_chip_specific_extensions.h to restore any registers unique to the RISC-V implementation. */
portasmRESTORE_ADDITIONAL_REGISTERS
-/* Load mstatus with the interrupt enable bits used by the task. */
-load_x t0, portMSTATUS_OFFSET * portWORD_SIZE( sp )
-csrw mstatus, t0 /* Required for MPIE bit. */
+#if( configENABLE_FPU == 1 )
+ csrr t0, mstatus
+ srl t1, t0, MSTATUS_FS_OFFSET
+ andi t1, t1, 3
+ addi t2, x0, 3
+ bne t1, t2, 3f /* If FPU status is not dirty, do not restore FPU registers. */
+
+ portcontextRESTORE_FPU_CONTEXT
+3:
+#endif /* ifdef portasmSTORE_FPU_CONTEXT */
load_x t0, portCRITICAL_NESTING_OFFSET * portWORD_SIZE( sp ) /* Obtain xCriticalNesting value for this task from task's stack. */
load_x t1, pxCriticalNesting /* Load the address of xCriticalNesting into t1. */
store_x t0, 0 ( t1 ) /* Restore the critical nesting value for this task. */
-load_x x1, 1 * portWORD_SIZE( sp )
-load_x x5, 2 * portWORD_SIZE( sp )
-load_x x6, 3 * portWORD_SIZE( sp )
-load_x x7, 4 * portWORD_SIZE( sp )
-load_x x8, 5 * portWORD_SIZE( sp )
-load_x x9, 6 * portWORD_SIZE( sp )
-load_x x10, 7 * portWORD_SIZE( sp )
-load_x x11, 8 * portWORD_SIZE( sp )
-load_x x12, 9 * portWORD_SIZE( sp )
-load_x x13, 10 * portWORD_SIZE( sp )
-load_x x14, 11 * portWORD_SIZE( sp )
-load_x x15, 12 * portWORD_SIZE( sp )
+load_x x1, 2 * portWORD_SIZE( sp )
+load_x x5, 3 * portWORD_SIZE( sp )
+load_x x6, 4 * portWORD_SIZE( sp )
+load_x x7, 5 * portWORD_SIZE( sp )
+load_x x8, 6 * portWORD_SIZE( sp )
+load_x x9, 7 * portWORD_SIZE( sp )
+load_x x10, 8 * portWORD_SIZE( sp )
+load_x x11, 9 * portWORD_SIZE( sp )
+load_x x12, 10 * portWORD_SIZE( sp )
+load_x x13, 11 * portWORD_SIZE( sp )
+load_x x14, 12 * portWORD_SIZE( sp )
+load_x x15, 13 * portWORD_SIZE( sp )
#ifndef __riscv_32e
- load_x x16, 13 * portWORD_SIZE( sp )
- load_x x17, 14 * portWORD_SIZE( sp )
- load_x x18, 15 * portWORD_SIZE( sp )
- load_x x19, 16 * portWORD_SIZE( sp )
- load_x x20, 17 * portWORD_SIZE( sp )
- load_x x21, 18 * portWORD_SIZE( sp )
- load_x x22, 19 * portWORD_SIZE( sp )
- load_x x23, 20 * portWORD_SIZE( sp )
- load_x x24, 21 * portWORD_SIZE( sp )
- load_x x25, 22 * portWORD_SIZE( sp )
- load_x x26, 23 * portWORD_SIZE( sp )
- load_x x27, 24 * portWORD_SIZE( sp )
- load_x x28, 25 * portWORD_SIZE( sp )
- load_x x29, 26 * portWORD_SIZE( sp )
- load_x x30, 27 * portWORD_SIZE( sp )
- load_x x31, 28 * portWORD_SIZE( sp )
+ load_x x16, 14 * portWORD_SIZE( sp )
+ load_x x17, 15 * portWORD_SIZE( sp )
+ load_x x18, 16 * portWORD_SIZE( sp )
+ load_x x19, 17 * portWORD_SIZE( sp )
+ load_x x20, 18 * portWORD_SIZE( sp )
+ load_x x21, 19 * portWORD_SIZE( sp )
+ load_x x22, 20 * portWORD_SIZE( sp )
+ load_x x23, 21 * portWORD_SIZE( sp )
+ load_x x24, 22 * portWORD_SIZE( sp )
+ load_x x25, 23 * portWORD_SIZE( sp )
+ load_x x26, 24 * portWORD_SIZE( sp )
+ load_x x27, 25 * portWORD_SIZE( sp )
+ load_x x28, 26 * portWORD_SIZE( sp )
+ load_x x29, 27 * portWORD_SIZE( sp )
+ load_x x30, 28 * portWORD_SIZE( sp )
+ load_x x31, 29 * portWORD_SIZE( sp )
#endif /* ifndef __riscv_32e */
addi sp, sp, portCONTEXT_SIZE
