From: Alexander Fedotov <alfedotov@gmail.com>
---
libgloss/arm/crt0.S | 135 +++++++++++++++++++------------------
newlib/libc/sys/arm/crt0.S | 18 ++---
2 files changed, 78 insertions(+), 75 deletions(-)
diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S
index c708f63d8..1deb73aa5 100644
--- a/libgloss/arm/crt0.S
+++ b/libgloss/arm/crt0.S
@@ -68,8 +68,10 @@
#endif
.endm
+/*******************************************************************************
+* Main library startup code.
+*******************************************************************************/
.align 0
-
FUNC_START _mainCRTStartup
FUNC_START _start
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
@@ -90,14 +92,14 @@
#endif
#endif
-/* Start by setting up a stack */
+/* Start by setting up a stack. */
#ifdef ARM_RDP_MONITOR
- /* Issue Demon SWI to read stack info */
- swi SWI_GetEnv /* Returns command line in r0 */
- mov sp,r1 /* and the highest memory address in r1 */
+ /* Issue Demon SWI to read stack info. */
+ swi SWI_GetEnv /* Returns command line in r0. */
+ mov sp,r1 /* and the highest memory address in r1. */
- /* stack limit is at end of data */
- /* allow slop for stack overflow handling and small frames */
+ /* Stack limit is at end of data. */
+ /* Allow slop for stack overflow handling and small frames. */
#ifdef THUMB1_ONLY
ldr r0, .LC2
adds r0, #128
@@ -109,19 +111,19 @@
#endif
#else
#ifdef ARM_RDI_MONITOR
- /* Issue Angel SWI to read stack info */
+ /* Issue Angel SWI to read stack info. */
movs r0, #AngelSWI_Reason_HeapInfo
- adr r1, .LC0 /* point at ptr to 4 words to receive data */
+ adr r1, .LC0 /* Point at ptr to 4 words to receive data. */
#ifdef THUMB_VXM
bkpt AngelSWI
#elif defined(__thumb2__)
- /* We are in thumb mode for startup on armv7 architectures. */
+ /* We are in thumb mode for startup on armv7 architectures. */
AngelSWIAsm (AngelSWI)
#else
- /* We are always in ARM mode for startup on pre armv7 archs. */
+ /* We are always in ARM mode for startup on pre armv7 archs. */
AngelSWIAsm (AngelSWI_ARM)
#endif
- ldr r0, .LC0 /* point at values read */
+ ldr r0, .LC0 /* Point at values read. */
/* Set __heap_limit. */
ldr r1, [r0, #4]
@@ -148,14 +150,15 @@
to skip setting sp/sl to 0 here.
- Considering M-profile processors, We might want to initialize
sp by the first entry of vector table and return 0 to SYS_HEAPINFO
- semihosting call, which will be skipped here. */
+ semihosting call, which will be skipped here. */
cmp r1, #0
beq .LC26
mov sp, r1
.LC26:
cmp r2, #0
beq .LC27
- /* allow slop for stack overflow handling and small frames */
+
+ /* Allow slop for stack overflow handling and small frames. */
#ifdef THUMB1_ONLY
adds r2, #128
adds r2, #128
@@ -163,9 +166,10 @@
#else
add sl, r2, #256
#endif
+
.LC27:
#else
- /* Set up the stack pointer to a fixed value */
+ /* Set up the stack pointer to a fixed value. */
/* Changes by toralf:
- Allow linker script to provide stack via __stack symbol - see
defintion of .Lstack
@@ -175,7 +179,7 @@
Loosely based on init.s from ARM/Motorola example code.
Note: Mode switch via CPSR is not allowed once in non-privileged
mode, so we take care not to enter "User" to set up its sp,
- and also skip most operations if already in that mode. */
+ and also skip most operations if already in that mode. */
ldr r3, .Lstack
cmp r3, #0
@@ -192,42 +196,42 @@
/* Note: This 'mov' is essential when starting in User, and ensures we
always get *some* sp value for the initial mode, even if we
have somehow missed it below (in which case it gets the same
- value as FIQ - not ideal, but better than nothing.) */
+ value as FIQ - not ideal, but better than nothing). */
mov sp, r3
#ifdef PREFER_THUMB
/* XXX Fill in stack assignments for interrupt modes. */
#else
mrs r2, CPSR
- tst r2, #0x0F /* Test mode bits - in User of all are 0 */
- beq .LC23 /* "eq" means r2 AND #0x0F is 0 */
- msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled */
+ tst r2, #0x0F /* Test mode bits - in User of all are 0. */
+ beq .LC23 /* "eq" means r2 AND #0x0F is 0. */
+ msr CPSR_c, #0xD1 /* FIRQ mode, interrupts disabled. */
mov sp, r3
- sub sl, sp, #0x1000 /* This mode also has its own sl (see below) */
+ sub sl, sp, #0x1000 /* This mode also has its own sl (see below). */
mov r3, sl
- msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled */
+ msr CPSR_c, #0xD7 /* Abort mode, interrupts disabled. */
mov sp, r3
sub r3, r3, #0x1000
- msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled */
+ msr CPSR_c, #0xDB /* Undefined mode, interrupts disabled. */
mov sp, r3
sub r3, r3, #0x1000
- msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled */
+ msr CPSR_c, #0xD2 /* IRQ mode, interrupts disabled. */
mov sp, r3
sub r3, r3, #0x2000
- msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled */
+ msr CPSR_c, #0xD3 /* Supervisory mode, interrupts disabled. */
mov sp, r3
- sub r3, r3, #0x8000 /* Min size 32k */
- bic r3, r3, #0x00FF /* Align with current 64k block */
+ sub r3, r3, #0x8000 /* Min size 32k. */
+ bic r3, r3, #0x00FF /* Align with current 64k block. */
bic r3, r3, #0xFF00
str r3, [r3, #-4] /* Move value into user mode sp without */
- ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm */
+ ldmdb r3, {sp}^ /* changing modes, via '^' form of ldm. */
orr r2, r2, #0xC0 /* Back to original mode, presumably SVC, */
- msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1 */
+ msr CPSR_c, r2 /* with FIQ/IRQ disable bits forced to 1. */
#endif
.LC23:
/* Setup a default stack-limit in-case the code has been
@@ -243,24 +247,24 @@
subs r2, r3, r2
mov sl, r2
#else
- sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl */
+ sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl. */
#endif
#endif
#endif
/* Zero the memory in the .bss section. */
- movs a2, #0 /* Second arg: fill value */
- mov fp, a2 /* Null frame pointer */
- mov r7, a2 /* Null frame pointer for Thumb */
+ movs a2, #0 /* Second arg: fill value. */
+ mov fp, a2 /* Null frame pointer. */
+ mov r7, a2 /* Null frame pointer for Thumb. */
- ldr a1, .LC1 /* First arg: start of memory block */
+ ldr a1, .LC1 /* First arg: start of memory block. */
ldr a3, .LC2
- subs a3, a3, a1 /* Third arg: length of block */
+ subs a3, a3, a1 /* Third arg: length of block. */
#if __thumb__ && !defined(PREFER_THUMB)
- /* Enter Thumb mode.... */
- add a4, pc, #1 /* Get the address of the Thumb block */
- bx a4 /* Go there and start Thumb decoding */
+ /* Enter Thumb mode... */
+ add a4, pc, #1 /* Get the address of the Thumb block. */
+ bx a4 /* Go there and start Thumb decoding. */
.code 16
.global __change_mode
@@ -271,9 +275,8 @@ __change_mode:
bl FUNCTION (memset)
#if !defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)
/* Changes by toralf: Taken from libgloss/m68k/crt0.S
- * initialize target specific stuff. Only execute these
- * functions it they exist.
- */
+ initialize target specific stuff. Only execute these
+ functions it they exist. */
ldr r3, .Lhwinit
cmp r3, #0
beq .LC24
@@ -285,24 +288,24 @@ __change_mode:
indirect_call r3
.LC25:
- movs r0, #0 /* no arguments */
- movs r1, #0 /* no argv either */
+ movs r0, #0 /* No arguments. */
+ movs r1, #0 /* No argv either. */
#else
- /* Need to set up standard file handles */
+ /* Need to set up standard file handles. */
bl FUNCTION (initialise_monitor_handles)
#ifdef ARM_RDP_MONITOR
- swi SWI_GetEnv /* sets r0 to point to the command line */
+ swi SWI_GetEnv /* Sets r0 to point to the command line. */
movs r1, r0
#else
movs r0, #AngelSWI_Reason_GetCmdLine
- ldr r1, .LC30 /* Space for command line */
+ ldr r1, .LC30 /* Space for command line. */
AngelSWIAsm (AngelSWI)
ldr r1, .LC30
ldr r1, [r1]
#endif
- /* Parse string at r1 */
- movs r0, #0 /* count of arguments so far */
+ /* Parse string at r1. */
+ movs r0, #0 /* Count of arguments so far. */
/* Push a NULL argument onto the end of the list. */
#ifdef __thumb__
push {r0}
@@ -310,7 +313,7 @@ __change_mode:
stmfd sp!, {r0}
#endif
.LC10:
-/* Skip leading blanks */
+/* Skip leading blanks. */
#ifdef __thumb__
ldrb r3, [r1]
adds r1, #1
@@ -322,7 +325,7 @@ __change_mode:
cmp r3, #' '
beq .LC10
-/* See whether we are scanning a string */
+/* See whether we are scanning a string. */
cmp r3, #'"'
#ifdef __thumb__
beq .LC20
@@ -333,17 +336,17 @@ __change_mode:
b .LC22
.LC21:
- movs r2, #' ' /* terminator type */
- subs r1, r1, #1 /* adjust back to point at start char */
+ movs r2, #' ' /* Terminator type. */
+ subs r1, r1, #1 /* Adjust back to point at start char. */
.LC22:
#else
cmpne r3, #'\''
moveq r2, r3
- movne r2, #' ' /* terminator type */
- subne r1, r1, #1 /* adjust back to point at start char */
+ movne r2, #' ' /* Terminator type. */
+ subne r1, r1, #1 /* Adjust back to point at start char. */
#endif
-/* Stack a pointer to the current argument */
+/* Stack a pointer to the current argument. */
#ifdef __thumb__
push {r1}
#else
@@ -359,16 +362,16 @@ __change_mode:
#endif
cmp r3, #0
beq .LC12
- cmp r2, r3 /* reached terminator? */
+ cmp r2, r3 /* Reached terminator ? */
bne .LC11
movs r2, #0
subs r3, r1, #1
- strb r2, [r3] /* terminate the arg string */
+ strb r2, [r3] /* Terminate the arg string. */
b .LC10
.LC12:
- mov r1, sp /* point at stacked arg pointers */
- /* We've now got the stacked args in order reverse the */
+ mov r1, sp /* Point at stacked arg pointers. */
+ /* We've now got the stacked args in order, reverse them. */
#ifdef __thumb__
movs r2, r0
lsls r2, #2
@@ -390,10 +393,10 @@ __change_mode:
bics r4, r5
mov sp, r4
#else
- add r2, sp, r0, LSL #2 /* End of args */
- mov r3, sp /* Start of args */
+ add r2, sp, r0, LSL #2 /* End of args. */
+ mov r3, sp /* Start of args. */
.LC13: cmp r2, r3
- ldrhi r4,[r2, #-4] /* Reverse ends of list */
+ ldrhi r4,[r2, #-4] /* Reverse ends of list. */
ldrhi r5, [r3]
strhi r5, [r2, #-4]!
strhi r4, [r3], #4
@@ -431,7 +434,6 @@ __change_mode:
#if __thumb__ && !defined(PREFER_THUMB)
/* Come out of Thumb mode. This code should be redundant. */
-
mov a4, pc
bx a4
@@ -447,7 +449,6 @@ change_back:
/* For Thumb, constants must be after the code since only
positive offsets are supported for PC relative addresses. */
-
.align 0
.LC0:
#ifdef ARM_RDI_MONITOR
@@ -457,13 +458,13 @@ change_back:
/* Changes by toralf: Provide alternative "stack" variable whose value
may be defined externally; .Lstack will be used instead of .LC0 if
it points to a non-0 value. Also set up references to "hooks" that
- may be used by the application to provide additional init code. */
-
+ may be used by the application to provide additional init code. */
#ifdef __pe__
.word 0x800000
#else
.word 0x80000 /* Top of RAM on the PIE board. */
#endif
+
.Lstack:
.word __stack
.Lhwinit:
@@ -476,7 +477,7 @@ change_back:
runtime (meaning "ignore setting") for the variables, when the user
does not provide the symbols. (The linker uses a weak symbol if,
and only if, a normal version of the same symbol isn't provided
- e.g. by a linker script or another object file.) */
+ e.g. by a linker script or another object file.) */
.weak __stack
.weak FUNCTION (hardware_init_hook)
diff --git a/newlib/libc/sys/arm/crt0.S b/newlib/libc/sys/arm/crt0.S
index 8c9f7be38..7a6b40d9a 100644
--- a/newlib/libc/sys/arm/crt0.S
+++ b/newlib/libc/sys/arm/crt0.S
@@ -50,13 +50,13 @@
.global \name
.thumb_func
\name:
-.endm
+.endm
#else
.code 32
.macro FUNC_START name
- .global \name
+ .global \name
\name:
-.endm
+.endm
#endif
.macro indirect_call reg
@@ -68,8 +68,10 @@
#endif
.endm
+/*******************************************************************************
+* Main library startup code.
+*******************************************************************************/
.align 0
-
FUNC_START _mainCRTStartup
FUNC_START _start
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
@@ -399,7 +401,7 @@ __change_mode:
bl FUNCTION (_init)
movs r0, r4
movs r1, r5
-#endif
+#endif
bl FUNCTION (main)
bl FUNCTION (exit) /* Should not return. */
@@ -420,7 +422,7 @@ change_back:
#endif
/* For Thumb, constants must be after the code since only
- positive offsets are supported for PC relative addresses. */
+ positive offsets are supported for PC relative addresses. */
.align 0
.LC0:
#ifdef ARM_RDI_MONITOR
@@ -430,7 +432,7 @@ change_back:
/* Changes by toralf: Provide alternative "stack" variable whose value
may be defined externally; .Lstack will be used instead of .LC0 if
it points to a non-0 value. Also set up references to "hooks" that
- may be used by the application to provide additional init code. */
+ may be used by the application to provide additional init code. */
#ifdef __pe__
.word 0x800000
#else
@@ -449,7 +451,7 @@ change_back:
runtime (meaning "ignore setting") for the variables, when the user
does not provide the symbols. (The linker uses a weak symbol if,
and only if, a normal version of the same symbol isn't provided
- e.g. by a linker script or another object file). */
+ e.g. by a linker script or another object file.) */
.weak __stack
.weak FUNCTION (hardware_init_hook)