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-rw-r--r--libgloss/arm/crt0.S139
1 files changed, 94 insertions, 45 deletions
diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S
index 823f409a4..28d2918b3 100644
--- a/libgloss/arm/crt0.S
+++ b/libgloss/arm/crt0.S
@@ -43,31 +43,54 @@
.fnstart
#endif
-/* Start by setting up a stack */
-#ifdef ARM_RDP_MONITOR
+ /* Start by setting up a stack */
+#ifdef _ARM_V7M
+ /* Copy .data into ram. */
+ ldr r0, =__data_load
+ ldr r1, =__data_start
+ cmp r0, r1 /* If LMA == VMA we are running from ram. */
+ beq 2f
+ ldr r2, =_edata
+ /* When running from ROM the stack pointer is set up at CPU reset. */
+ /* Copy .data into RAM. */
+1:
+ ldr r3, [r0], #4
+ str r3, [r1], #4
+ cmp r1, r2
+ blt 1b
+ b 3f
+2:
+ /* Set the stack pointer when running from RAM. */
+ ldr r0, .Lstack
+ cmp r0, #0
+ beq 3f
+ mov sp, r0
+3:
+#else
+# 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 */
ldr sl, .LC2 /* stack limit is at end of data */
add sl, sl, #256 /* allow slop for stack overflow handling */
/* and small frames */
-#else
-#ifdef ARM_RDI_MONITOR
+# else
+# ifdef ARM_RDI_MONITOR
/* Issue Angel SWI to read stack info */
mov r0, #AngelSWI_Reason_HeapInfo
adr r1, .LC0 /* point at ptr to 4 words to receive data */
-#if defined(__thumb2__)
+# if defined(__thumb2__)
bkpt AngelSWI
-#else
+# else
/* We are always in ARM mode for startup */
AngelSWIAsm AngelSWI_ARM
-#endif
+# endif
ldr r0, .LC0 /* point at values read */
ldr sp, [r0, #8]
ldr sl, [r0, #12]
add sl, sl, #256 /* allow slop for stack overflow handling */
/* and small frames */
-#else
+# else
/* Set up the stack pointer to a fixed value */
/* Changes by toralf:
- Allow linker script to provide stack via __stack symbol - see
@@ -127,9 +150,11 @@
this default 64k is enough for the program being executed.
However, it ensures that this simple crt0 world will not
immediately cause an overflow event: */
- sub sl, r3, #64 << 10 /* Still assumes 256bytes below sl */
-#endif
+ sub sl, sp, #64 << 10 /* Still assumes 256bytes below sl */
+# endif
+# endif
#endif
+
/* Zero the memory in the .bss section. */
mov a2, #0 /* Second arg: fill value */
mov fp, a2 /* Null frame pointer */
@@ -152,7 +177,11 @@ __change_mode:
#endif
bl FUNCTION (memset)
-#if !defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)
+ /* For ARM V7M, we do not want to have semihosting traps in
+ crt0.o, so that people can use the same programs both with
+ and without semihosting. */
+#if ((!defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)) \
+ || defined (_ARM_V7M))
/* Changes by toralf: Taken from libgloss/m68k/crt0.S
* initialize target specific stuff. Only execute these
* functions it they exist.
@@ -172,34 +201,31 @@ __change_mode:
mov r0, #0 /* no arguments */
mov r1, #0 /* no argv either */
#else
- /* Need to set up standard file handles */
- bl FUNCTION (initialise_monitor_handles)
-
-#ifdef ARM_RDP_MONITOR
+# ifdef ARM_RDP_MONITOR
swi SWI_GetEnv /* sets r0 to point to the command line */
mov r1, r0
-#else
+# else
mov r0, #AngelSWI_Reason_GetCmdLine
adr r1, .LC30 /* Space for command line */
AngelSWIAsm AngelSWI
ldr r1, .LC30
-#endif
+# endif
/* Parse string at r1 */
mov r0, #0 /* count of arguments so far */
/* Push a NULL argument onto the end of the list. */
-#ifdef __thumb__
+# ifdef __thumb__
push {r0}
-#else
+# else
stmfd sp!, {r0}
-#endif
+# endif
.LC10:
/* Skip leading blanks */
-#ifdef __thumb__
+# ifdef __thumb__
ldrb r3, [r1]
add r1, #1
-#else
+# else
ldrb r3, [r1], #1
-#endif
+# endif
cmp r3, #0
beq .LC12
cmp r3, #' '
@@ -207,7 +233,7 @@ __change_mode:
/* See whether we are scanning a string */
cmp r3, #'"'
-#ifdef __thumb__
+# ifdef __thumb__
beq .LC20
cmp r3, #'\''
bne .LC21
@@ -219,27 +245,27 @@ __change_mode:
mov r2, #' ' /* terminator type */
sub r1, r1, #1 /* adjust back to point at start char */
.LC22:
-#else
+# else
cmpne r3, #'\''
moveq r2, r3
movne r2, #' ' /* terminator type */
subne r1, r1, #1 /* adjust back to point at start char */
-#endif
+# endif
/* Stack a pointer to the current argument */
-#ifdef __thumb__
+# ifdef __thumb__
push {r1}
-#else
+# else
stmfd sp!, {r1}
-#endif
+# endif
add r0, r0, #1
.LC11:
-#ifdef __thumb__
+# ifdef __thumb__
ldrb r3, [r1]
add r1, #1
-#else
+# else
ldrb r3, [r1], #1
-#endif
+# endif
cmp r3, #0
beq .LC12
cmp r2, r3 /* reached terminator? */
@@ -252,7 +278,7 @@ __change_mode:
.LC12:
mov r1, sp /* point at stacked arg pointers */
/* We've now got the stacked args in order reverse the */
-#ifdef __thumb__
+# ifdef __thumb__
mov r2, r0
lsl r2, #2
add r2, sp
@@ -272,7 +298,7 @@ __change_mode:
mov r5, #7
bic r4, r5
mov sp, r4
-#else
+# else
add r2, sp, r0, LSL #2 /* End of args */
mov r3, sp /* Start of args */
.LC13: cmp r2, r3
@@ -283,7 +309,7 @@ __change_mode:
bhi .LC13
/* Ensure doubleword stack alignment. */
bic sp, sp, #7
-#endif
+# endif
#endif
#ifdef __USES_INITFINI__
@@ -323,21 +349,27 @@ change_back:
positive offsets are supported for PC relative addresses. */
.align 0
+#ifndef _ARM_V7M
.LC0:
-#ifdef ARM_RDI_MONITOR
+# ifdef ARM_RDI_MONITOR
.word HeapBase
-#else
-#ifndef ARM_RDP_MONITOR
+# else
+# ifndef ARM_RDP_MONITOR
/* 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. */
-#ifdef __pe__
+# ifdef __pe__
.word 0x800000
-#else
+# else
.word 0x80000 /* Top of RAM on the PIE board. */
-#endif
+# endif
+# endif
+# endif
+#endif
+#if ((!defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)) \
+ || defined (_ARM_V7M))
.Lstack:
.word __stack
.Lhwinit:
@@ -352,15 +384,17 @@ change_back:
and only if, a normal version of the same symbol isn't provided
e.g. by a linker script or another object file.) */
- .set __stack, 0
.set FUNCTION (hardware_init_hook), 0
.set FUNCTION (software_init_hook), 0
- .weak __stack
.weak FUNCTION (hardware_init_hook)
.weak FUNCTION (software_init_hook)
+
+ /* For ARMV7M we want to error if no stack location is defined. */
+#if !defined(_ARM_V7M)
+ .set __stack, 0
+ .weak __stack
#endif
-
#endif
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
/* Protect against unhandled exceptions. */
@@ -375,7 +409,7 @@ change_back:
.Lfini:
.word FUNCTION(_fini)
#endif
-#ifdef ARM_RDI_MONITOR
+#if defined(ARM_RDI_MONITOR) && !defined(_ARM_V7M)
.LC30:
.word CommandLine
.word 255
@@ -395,3 +429,18 @@ CommandLine: .space 256,0 /* Maximum length of 255 chars handled. */
.section .idata$3
.long 0,0,0,0,0,0,0,0
#endif
+
+#ifdef _ARM_V7M
+ /* The hardware uses this vector to handle hardware resets and
+ exceptions. */
+ .section .isr_vector, "a"
+ /* The value for the stack pointer at reset. */
+ .word __stack
+ /* The value for the PC at reset. */
+ .word _start
+ /* The value for the PC if an NMI occurs. */
+ .word _nmi_isr
+ /* The value for the PC if a fault occurs. */
+ .word _fault_isr
+#endif /* _ARM_V7M */
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-16 10:42:17 +0000