Implement vfork() for the MIPS32 architecture

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5520 42af7a65-404d-4744-a932-0658087f49c3

nuttx/arch/arm/src/arm/vfork.S

@@ -105,6 +105,7 @@ vfork:
 	mov		r0, sp					/* Save the value of the stack on entry */
 	sub		sp, sp, #VFORK_SIZEOF	/* Allocate the structure on the stack */
 
+	/* CPU registers */
 	/* Save the volatile registers */
 
 	str		r4, [sp, #VFORK_R4_OFFSET]
@@ -121,6 +122,8 @@ vfork:
 	str		r0, [sp, #VFORK_SP_OFFSET]
 	str		lr, [sp, #VFORK_LR_OFFSET]
 
+	/* Floating point registers (not yet) */
+
 	/* Then, call up_vfork(), passing it a pointer to the stack structure */
 
 	mov		r0, sp

nuttx/arch/arm/src/armv7-m/vfork.S

@@ -108,6 +108,7 @@ vfork:
 	mov		r0, sp					/* Save the value of the stack on entry */
 	sub		sp, sp, #VFORK_SIZEOF	/* Allocate the structure on the stack */
 
+	/* CPU registers */
 	/* Save the volatile registers */
 
 	str		r4, [sp, #VFORK_R4_OFFSET]
@@ -124,6 +125,8 @@ vfork:
 	str		r0, [sp, #VFORK_SP_OFFSET]
 	str		lr, [sp, #VFORK_LR_OFFSET]
 
+	/* Floating point registers (not yet) */
+
 	/* Then, call up_vfork(), passing it a pointer to the stack structure */
 
 	mov		r0, sp

nuttx/arch/arm/src/common/up_vfork.c

@@ -208,7 +208,7 @@ pid_t up_vfork(const struct vfork_s *context)
   svdbg("New stack base:%08x SP:%08x FP:%08x\n",
         child->adj_stack_ptr, newsp, newfp);
 
- /* Update the stack pointer, frame pointer, and voltile registers.  When
+ /* Update the stack pointer, frame pointer, and volatile registers.  When
   * the child TCB was initialized, all of the values were set to zero.
   * up_initial_state() altered a few values, but the return value in R0
   * should be cleared to zero, providing the indication to the newly started

nuttx/arch/arm/src/common/up_vfork.h

@@ -1,5 +1,5 @@
 /****************************************************************************
- * arch/arm/src/common/arm-vfork.h
+ * arch/arm/src/common/up_vfork.h
  *
  *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
@@ -53,6 +53,7 @@
 #define VFORK_R8_OFFSET  (4*4)   /* Volatile register r8 */
 #define VFORK_R9_OFFSET  (5*4)   /* Volatile register r9 */
 #define VFORK_R10_OFFSET (6*4)   /* Volatile register r10 */
+
 #define VFORK_FP_OFFSET  (7*4)   /* Frame pointer */
 #define VFORK_SP_OFFSET  (8*4)   /* Stack pointer*/
 #define VFORK_LR_OFFSET  (9*4)   /* Return address*/
@@ -66,6 +67,8 @@
 #ifndef __ASSEMBLY__
 struct vfork_s
 {
+  /* CPU registers */
+
   uint32_t r4;   /* Volatile register r4 */
   uint32_t r5;   /* Volatile register r5 */
   uint32_t r6;   /* Volatile register r6 */
@@ -73,9 +76,12 @@ struct vfork_s
   uint32_t r8;   /* Volatile register r8 */
   uint32_t r9;   /* Volatile register r9 */
   uint32_t r10;  /* Volatile register r10 */
+
   uint32_t fp;   /* Frame pointer */
   uint32_t sp;   /* Stack pointer*/
   uint32_t lr;   /* Return address*/
+
+  /* Floating point registers (not yet) */
 };
 #endif