[libcpu][arm926] Remove unused SPSR register PUSH/POP when os switch thread.

libcpu/arm/arm926/context_gcc.S

@@ -53,14 +53,10 @@ rt_hw_context_switch:
     stmfd   sp!, {r0-r12, lr}       @; push lr & register file
     mrs     r4, cpsr
     stmfd   sp!, {r4}               @; push cpsr
-    mrs     r4, spsr
-    stmfd   sp!, {r4}               @; push spsr
     str     sp, [r0]                @; store sp in preempted tasks tcb
     ldr     sp, [r1]                @; get new task stack pointer
     ldmfd   sp!, {r4}               @; pop new task spsr
     msr     spsr_cxsf, r4
-    ldmfd   sp!, {r4}               @; pop new task cpsr
-    msr     spsr_cxsf, r4
     ldmfd   sp!, {r0-r12, lr, pc}^  @; pop new task r0-r12, lr & pc
 
 /*
@@ -70,9 +66,6 @@ rt_hw_context_switch:
     .globl rt_hw_context_switch_to
 rt_hw_context_switch_to:
     ldr     sp, [r0]                @; get new task stack pointer
-
-    ldmfd   sp!, {r4}               @; pop new task spsr
-    msr     spsr_cxsf, r4
     ldmfd   sp!, {r4}               @; pop new task cpsr
     msr     spsr_cxsf, r4
     ldmfd   sp!, {r0-r12, lr, pc}^  @; pop new task r0-r12, lr & pc

libcpu/arm/arm926/context_iar.S

@@ -55,14 +55,10 @@ rt_hw_context_switch:
     STMFD   SP!, {R0-R12, LR}       ; push lr & register file
     MRS     R4, CPSR
     STMFD   SP!, {R4}               ; push cpsr
-    MRS     R4, SPSR
-    STMFD   SP!, {R4}               ; push spsr
     STR     SP, [R0]                ; store sp in preempted tasks TCB
     LDR     SP, [R1]                ; get new task stack pointer
     LDMFD   SP!, {R4}               ; pop new task spsr
     MSR     SPSR_cxsf, R4
-    LDMFD   SP!, {R4}               ; pop new task cpsr
-    MSR     SPSR_cxsf, R4
     LDMFD   SP!, {R0-R12, LR, PC}^  ; pop new task r0-r12, lr & pc
 
 /*
@@ -72,12 +68,8 @@ rt_hw_context_switch:
     PUBLIC rt_hw_context_switch_to
 rt_hw_context_switch_to:
     LDR     SP, [R0]                ; get new task stack pointer
-
     LDMFD   SP!, {R4}               ; pop new task spsr
     MSR     SPSR_cxsf, R4
-    LDMFD   SP!, {R4}               ; pop new task cpsr
-    MSR     SPSR_cxsf, R4
-
     LDMFD   SP!, {R0-R12, LR, PC}^   ; pop new task r0-r12, lr & pc
 
 /*

libcpu/arm/arm926/context_rvds.S

@@ -60,14 +60,10 @@ rt_hw_context_switch    proc
     stmfd   sp!, {r0-r12, lr}       ; push lr & register file
     mrs     r4, cpsr
     stmfd   sp!, {r4}               ; push cpsr
-    mrs     r4, spsr
-    stmfd   sp!, {r4}               ; push spsr
     str     sp, [r0]                ; store sp in preempted tasks tcb
     ldr     sp, [r1]                ; get new task stack pointer
     ldmfd   sp!, {r4}               ; pop new task spsr
     msr     spsr_cxsf, r4
-    ldmfd   sp!, {r4}               ; pop new task cpsr
-    msr     spsr_cxsf, r4
     ldmfd   sp!, {r0-r12, lr, pc}^  ; pop new task r0-r12, lr & pc
     endp
 
@@ -78,11 +74,8 @@ rt_hw_context_switch    proc
 rt_hw_context_switch_to    proc
     export rt_hw_context_switch_to
     ldr     sp, [r0]                ; get new task stack pointer
-
     ldmfd   sp!, {r4}               ; pop new task spsr
     msr     spsr_cxsf, r4
-    ldmfd   sp!, {r4}               ; pop new task cpsr
-    msr     spsr_cxsf, r4
     ldmfd   sp!, {r0-r12, lr, pc}^   ; pop new task r0-r12, lr & pc
     endp
 

libcpu/arm/arm926/stack.c

@@ -66,8 +66,11 @@ rt_uint8_t *rt_hw_stack_init(void *tentry, void *parameter,
     *(--stk) = 0;                           /* r2 */
     *(--stk) = 0;                           /* r1 */
     *(--stk) = (rt_uint32_t)parameter;      /* r0 : argument */
-    *(--stk) = SVCMODE;                     /* cpsr */
-    *(--stk) = SVCMODE;                     /* spsr */
+	/* cpsr */
+	if ((rt_uint32_t)tentry & 0x01)
+		*(--stk) = SVCMODE | 0x20;			/* thumb mode */
+	else
+		*(--stk) = SVCMODE;					/* arm mode   */
 
     /* return task's current stack address */
     return (rt_uint8_t *)stk;

libcpu/arm/arm926/start_gcc.S

@@ -291,24 +291,19 @@ rt_hw_context_switch_interrupt_do:
     STR     R1,  [R0]               @; Save to flag variable
 
     LDMFD   SP!, {R0-R12,LR}        @; Reload saved registers
-    STMFD   SP!, {R0-R3}            @; Save R0-R3
-    MOV     R1,  SP                 @; Save old task's SP to R1
-    ADD     SP,  SP, #16            @; Restore SP
+    STMFD   SP, {R0-R2}             @; Save R0-R2
+    SUB     R1,  SP, #4*3           @; Save old task's SP to R1
     SUB     R2,  LR, #4             @; Save old task's PC to R2
 
-    MRS     R3,  SPSR               @; Get CPSR of interrupt thread
-    
+    MRS     R0,  SPSR               @; Get CPSR of interrupt thread
+
     MSR     CPSR_c, #MODE_SVC|NOINT @; Switch to SVC mode and no interrupt
 
     STMFD   SP!, {R2}               @; Push old task's PC
-    STMFD   SP!, {R4-R12,LR}        @; Push old task's LR,R12-R4
-    MOV     R4,  R1                 @; Special optimised code below
-    MOV     R5,  R3
-    LDMFD   R4!, {R0-R3}
-    STMFD   SP!, {R0-R3}            @; Push old task's R3-R0
-    STMFD   SP!, {R5}               @; Push old task's CPSR
-    MRS     R4,  SPSR
-    STMFD   SP!, {R4}               @; Push old task's SPSR
+    STMFD   SP!, {R3-R12,LR}        @; Push old task's LR,R12-R3
+    LDMFD   R1, {R1-R3}
+    STMFD   SP!, {R1-R3}            @; Push old task's R2-R0
+    STMFD   SP!, {R0}               @; Push old task's CPSR
 
     LDR     R4,  =rt_interrupt_from_thread
     LDR     R5,  [R4]               @; R5 = stack ptr in old tasks's TCB
@@ -320,7 +315,5 @@ rt_hw_context_switch_interrupt_do:
 
     LDMFD   SP!, {R4}               @; Pop new task's SPSR
     MSR     SPSR_cxsf, R4
-    LDMFD   SP!, {R4}               @; Pop new task's CPSR
-    MSR     SPSR_cxsf, R4
 
-    LDMFD   SP!, {R0-R12,LR,PC}^     @; pop new task's R0-R12,LR & PC
+    LDMFD   SP!, {R0-R12,LR,PC}^    @; pop new task's R0-R12,LR & PC SPSR 2 CPSR

libcpu/arm/arm926/start_iar.S

@@ -262,24 +262,19 @@ rt_hw_context_switch_interrupt_do:
     STR     R1,  [R0]               ; Save to flag variable
 
     LDMFD   SP!, {R0-R12,LR}        ; Reload saved registers
-    STMFD   SP!, {R0-R3}            ; Save R0-R3
-    MOV     R1,  SP                 ; Save old task's SP to R1
-    ADD     SP,  SP, #16            ; Restore SP
+    STMFD   SP, {R0-R2}             ; Save R0-R2
+    SUB     R1,  SP, #4*3           ; Save old task's SP to R1
     SUB     R2,  LR, #4             ; Save old task's PC to R2
 
-    MRS     R3,  SPSR               ; Get CPSR of interrupt thread
+    MRS     R0,  SPSR               ; Get CPSR of interrupt thread
 
     MSR     CPSR_c, #MODE_SVC|NOINT ; Switch to SVC mode and no interrupt
 
     STMFD   SP!, {R2}               ; Push old task's PC
-    STMFD   SP!, {R4-R12,LR}        ; Push old task's LR,R12-R4
-    MOV     R4,  R1                 ; Special optimised code below
-    MOV     R5,  R3
-    LDMFD   R4!, {R0-R3}
-    STMFD   SP!, {R0-R3}            ; Push old task's R3-R0
-    STMFD   SP!, {R5}               ; Push old task's CPSR
-    MRS     R4,  SPSR
-    STMFD   SP!, {R4}               ; Push old task's SPSR
+    STMFD   SP!, {R3-R12,LR}        ; Push old task's LR,R12-R3
+    LDMFD   R1, {R1-R3}
+    STMFD   SP!, {R1-R3}            ; Push old task's R2-R0
+    STMFD   SP!, {R0}               ; Push old task's CPSR
 
     LDR     R4,  =rt_interrupt_from_thread
     LDR     R5,  [R4]               ; R5 = stack ptr in old tasks's TCB
@@ -291,8 +286,6 @@ rt_hw_context_switch_interrupt_do:
 
     LDMFD   SP!, {R4}               ; Pop new task's SPSR
     MSR     SPSR_cxsf, R4
-    LDMFD   SP!, {R4}               ; Pop new task's CPSR
-    MSR     SPSR_cxsf, R4
 
-    LDMFD   SP!, {R0-R12,LR,PC}^     ; pop new task's R0-R12,LR & PC
+    LDMFD   SP!, {R0-R12,LR,PC}^    ; pop new task's R0-R12,LR & PC SPSR to CPSR
     END

libcpu/arm/arm926/start_rvds.S

@@ -274,24 +274,19 @@ rt_hw_context_switch_interrupt_do PROC
     STR     R1,  [R0]               ; Save to flag variable
 
     LDMFD   SP!, {R0-R12,LR}        ; Reload saved registers
-    STMFD   SP!, {R0-R3}            ; Save R0-R3
-    MOV     R1,  SP                 ; Save old task's SP to R1
-    ADD     SP,  SP, #16            ; Restore SP
+    STMFD   SP, {R0-R2}             ; Save R0-R2
+    SUB     R1,  SP, #4*3           ; Save old task's SP to R1
     SUB     R2,  LR, #4             ; Save old task's PC to R2
 
-    MRS     R3,  SPSR               ; Get CPSR of interrupt thread
+    MRS     R0,  SPSR               ; Get CPSR of interrupt thread
 
     MSR     CPSR_c, #MODE_SVC:OR:NOINT  ; Switch to SVC mode and no interrupt
 
     STMFD   SP!, {R2}               ; Push old task's PC
-    STMFD   SP!, {R4-R12,LR}        ; Push old task's LR,R12-R4
-    MOV     R4,  R1                 ; Special optimised code below
-    MOV     R5,  R3
-    LDMFD   R4!, {R0-R3}
-    STMFD   SP!, {R0-R3}            ; Push old task's R3-R0
-    STMFD   SP!, {R5}               ; Push old task's CPSR
-    MRS     R4,  SPSR
-    STMFD   SP!, {R4}               ; Push old task's SPSR
+    STMFD   SP!, {R3-R12,LR}        ; Push old task's LR,R12-R3
+    LDMFD   R1, {R1-R3}
+    STMFD   SP!, {R1-R3}            ; Push old task's R2-R0
+    STMFD   SP!, {R0}               ; Push old task's CPSR
 
     LDR     R4,  =rt_interrupt_from_thread
     LDR     R5,  [R4]               ; R5 = stack ptr in old tasks's TCB
@@ -303,10 +298,8 @@ rt_hw_context_switch_interrupt_do PROC
 
     LDMFD   SP!, {R4}               ; Pop new task's SPSR
     MSR     SPSR_cxsf, R4
-    LDMFD   SP!, {R4}               ; Pop new task's CPSR
-    MSR     SPSR_cxsf, R4
 
-    LDMFD   SP!, {R0-R12,LR,PC}^     ; pop new task's R0-R12,LR & PC
+    LDMFD   SP!, {R0-R12,LR,PC}^    ; pop new task's R0-R12,LR & PC SPSR to CPSR
     ENDP
 
     IF  :DEF:__MICROLIB