risc-v reduce use 128 bytes irq stack

arch/risc-v/rv32i/gcc/port_c.c

@@ -31,3 +31,11 @@ __PORT__ void port_systick_config(uint32_t cycle_per_tick)
     *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = 0xFFFFFFFF & (mtimecmp >> 32);
     *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = 0xFFFFFFFF & (mtimecmp >>  0);
 }
+
+
+
+int k_task_irq_switch_flag = 0;
+__PORT__ void port_irq_context_switch()
+{
+    k_task_irq_switch_flag = 1;
+}

arch/risc-v/rv32i/gcc/port_s.S

@@ -10,19 +10,19 @@
 
 .global port_sched_start
 .global port_context_switch
-.global port_irq_context_switch
 
 .extern k_curr_task
 .extern k_next_task
+.extern k_task_irq_switch_flag
 
-#define MSTATUS_MIE         0x00000008
-#define MSTATUS_MPP         0x00001800
+.equ    MSTATUS_MIE,        0x00000008
+.equ    MSTATUS_MPP,        0x00001800
 
-#define MIE_MTIE            (1 << 7)
+.equ    MIE_MTIE,           (1 << 7)        // machine mode interrupt enable
 
-#define MIP_MTIP            (1 << 7)
+.equ    MIP_MTIP,           (1 << 7)        // machine mode timer interrupt pending
 
-#define REGBYTES            4
+.equ    REGBYTES,           4
 
 .text
 .align 2
@@ -192,36 +192,6 @@ port_context_switch:
 
     mret
 
-
-.align 2
-.type port_irq_context_switch, %function
-port_irq_context_switch:
-    SAVE_CONTEXT
-
-    sw      ra,  0*REGBYTES(sp)
-
-    li      t0,  MSTATUS_MPP
-    sw     t0,  1*REGBYTES(sp)
-
-    // save sp to k_curr_task.sp
-    la      t0, k_curr_task         // t0 = &k_curr_task
-    lw      t1, (t0)
-    sw      sp, (t1)
-
-    // switch task
-    // k_curr_task = k_next_task
-    la      t1, k_next_task         // t1 = &k_next_task
-    lw      t1, (t1)                // t1 = k_next_task
-    sw      t1, (t0)
-
-    // load new task sp
-    lw      sp, (t1)
-
-    RESTORE_CONTEXT
-
-    mret
-
-
 .align 2
 .global trap_entry
 .global irq_entry
@@ -244,13 +214,33 @@ irq_entry:
     mv      a1,  sp
     bltz    a0,  irq
     call    cpu_trap_entry
-    j       restore
+    j       irq_restore
+
 irq:
-    slli    a0, a0, 16
-    srli    a0, a0, 16
+    slli    a0,  a0, 16
+    srli    a0,  a0, 16
     call    cpu_irq_entry
-restore:
+
+    la      t0,  k_task_irq_switch_flag 
+    lw      t1,  (t0)
+    beqz    t1,  irq_restore
+    sw      zero,(t0)
+
+    // save sp to k_curr_task.sp
+    la      t0, k_curr_task         // t0 = &k_curr_task
+    lw      t1, (t0)
+    sw      sp, (t1)
+
+    // switch task
+    // k_curr_task = k_next_task
+    la      t1, k_next_task         // t1 = &k_next_task
+    lw      t1, (t1)                // t1 = k_next_task
+    sw      t1, (t0)
+
+    // load new task sp
+    lw      sp, (t1)
+
+irq_restore:
     RESTORE_CONTEXT
 
     mret
-

board/GD32VF103C_START/eclipse/hello_world/main.c

@@ -27,7 +27,7 @@ void task2(void *pdata)
         share++;
         for(int i=0; i<5; i++) {
             printf("hello world from %s cnt: %08x\n", __func__, task_cnt2--);
-            tos_task_delay(200);
+            tos_task_delay(10);
         }
         tos_sem_post(&sem);
     }

board/QEMU_Spike/Src/main.c

@@ -14,11 +14,8 @@ void task1(void *pdata)
 	{
 		t1++;
 		share++;
-		//k_tick_t delay = tos_millisec2tick(10);
-		//tos_task_delay(delay);
-		tos_task_yield();
-		//osDelay(10);
-		//asm("wfi;");
+		tos_task_delay(2);
+		//tos_task_yield();
 	}
 }
 
@@ -29,9 +26,9 @@ void task2(void *pdata)
 	{
 		t2--;
 		share--;
-		//tos_task_delay(10);
-		tos_task_yield();
-		asm("wfi;");
+		tos_task_delay(3);
+		//tos_task_yield();
+		//asm("wfi;");
 	}
 }