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[patch] Arm Thumb-2 support
- From: Paul Brook <paul at codesourcery dot com>
- To: newlib at sourceware dot org
- Date: Tue, 7 Feb 2006 17:18:43 +0000
- Subject: [patch] Arm Thumb-2 support
The attached patch allows building Arm newlib/libgloss in Thumb-2 mode. Future
Arm CPUs will implement Thumb-2 only and not Arm mode, so the existing Thumb
support is not sufficient. The patch makes two changes:
- Add pure Thumb-2 startup code.
- Use the BKPT instruction instead of SWI for semihosted syscalls.
Tested with cross to arm-none-eabi.
Ok?
Paul
2006-02-07 Paul Brook <paul@codesourcery.com>
libgloss/
* arm/crt0.S: Add Thumb-2 startup code.
* arm/redboot-crt0.S: Ditto.
* arm/libcfunc.c (do_AngelSWI): Use AngelSWIInsn.
* arm/swi.h (AngelSWIInsn, AngelSWIAsm): Define.
* arm/trap.S: Disable for Thumb-2.
newlib/
* libc/machine/arm/setjmp.S: Add Thumb-2 support.
* libc/sys/arm/crt0.S: Add Thumb-2 startup code.
* libc/sys/arm/libcfunc.c (do_AngelSWI): Use AngelSWIInsn.
* libc/sys/arm/swi.h (AngelSWIInsn, AngelSWIAsm): Define.
* libc/sys/arm/trap.S: Disable for Thumb-2.
Index: libgloss/arm/crt0.S
===================================================================
RCS file: /var/cvsroot/src-cvs/src/libgloss/arm/crt0.S,v
retrieving revision 1.4
diff -u -p -r1.4 crt0.S
--- libgloss/arm/crt0.S 19 Jul 2005 15:15:25 -0000 1.4
+++ libgloss/arm/crt0.S 7 Feb 2006 16:44:11 -0000
@@ -18,15 +18,26 @@
/* .text is used instead of .section .text so it works with arm-aout too. */
.text
+#if defined(__thumb2__)
+ .syntax unified
+ .thumb
+.macro FUNC_START name
+ .global \name
+ .thumb_func
+\name:
+.endm
+#else
.code 32
+.macro FUNC_START name
+ .global \name
+\name:
+.endm
+#endif
.align 0
- .global _mainCRTStartup
- .global _start
- .global start
-start:
-_start:
-_mainCRTStartup:
+ FUNC_START _mainCRTStartup
+ FUNC_START _start
+ FUNC_START start
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
/* Annotation for EABI unwinding tables. */
.fnstart
@@ -45,7 +56,12 @@ _mainCRTStartup:
/* Issue Angel SWI to read stack info */
mov r0, #AngelSWI_Reason_HeapInfo
adr r1, .LC0 /* point at ptr to 4 words to receive data */
- swi AngelSWI_ARM /* We are always in ARM mode for startup */
+#if defined(__thumb2__)
+ bkpt AngelSWI
+#else
+ /* We are always in ARM mode for startup */
+ AngelSWIAsm AngelSWI_ARM
+#endif
ldr r0, .LC0 /* point at values read */
ldr sp, [r0, #8]
ldr sl, [r0, #12]
@@ -124,8 +140,8 @@ _mainCRTStartup:
sub a3, a3, a1 /* Third arg: length of block */
-#ifdef __thumb__ /* Enter Thumb mode.... */
-
+#if defined(__thumb__) && !defined(__thumb2__)
+ /* Enter Thumb mode.... */
add a4, pc, #1 /* Get the address of the Thumb block */
bx a4 /* Go there and start Thumb decoding */
@@ -165,7 +181,7 @@ __change_mode:
#else
mov r0, #AngelSWI_Reason_GetCmdLine
adr r1, .LC30 /* Space for command line */
- swi AngelSWI
+ AngelSWIAsm AngelSWI
ldr r1, .LC30
#endif
/* Parse string at r1 */
@@ -287,7 +303,7 @@ __change_mode:
bl FUNCTION (exit) /* Should not return. */
-#ifdef __thumb__
+#if defined(__thumb__) && !defined(__thumb2__)
/* Come out of Thumb mode. This code should be redundant. */
mov a4, pc
Index: libgloss/arm/libcfunc.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/libgloss/arm/libcfunc.c,v
retrieving revision 1.6
diff -u -p -r1.6 libcfunc.c
--- libgloss/arm/libcfunc.c 30 Nov 2005 23:37:14 -0000 1.6
+++ libgloss/arm/libcfunc.c 7 Feb 2006 16:04:27 -0000
@@ -15,7 +15,7 @@ static inline int
do_AngelSWI (int reason, void * arg)
{
int value;
- asm volatile ("mov r0, %1; mov r1, %2; swi %a3; mov %0, r0"
+ asm volatile ("mov r0, %1; mov r1, %2; " AngelSWIInsn " %a3; mov %0, r0"
: "=r" (value) /* Outputs */
: "r" (reason), "r" (arg), "i" (AngelSWI) /* Inputs */
: "r0", "r1", "lr"
Index: libgloss/arm/redboot-crt0.S
===================================================================
RCS file: /var/cvsroot/src-cvs/src/libgloss/arm/redboot-crt0.S,v
retrieving revision 1.4
diff -u -p -r1.4 redboot-crt0.S
--- libgloss/arm/redboot-crt0.S 7 Nov 2002 00:25:57 -0000 1.4
+++ libgloss/arm/redboot-crt0.S 2 Feb 2006 17:13:54 -0000
@@ -12,11 +12,23 @@
.text
/* Setup the assembly entry point. */
- .code 32
- .globl SYM_NAME(start)
- .globl SYM_NAME(_start)
-SYM_NAME(start):
-SYM_NAME(_start):
+#ifdef __thumb2__
+.macro FUNC_START name
+ .global \name
+ .thumb_func
+\name:
+.endm
+ .syntax unified
+ .thumb
+#else
+.macro FUNC_START name
+ .global \name
+\name:
+.endm
+ .code 32
+#endif
+ FUNC_START SYM_NAME(start)
+ FUNC_START SYM_NAME(_start)
mov fp, #0 /* Null frame pointer. */
mov r7, #0 /* Null frame pointer for Thumb. */
@@ -46,7 +58,7 @@ SYM_NAME(_start):
/* Nothing to left to clear. */
#endif
-#ifdef __thumb__ /* Enter Thumb mode. */
+#if defined(__thumb__) && !defined(__thumb2__) /* Enter Thumb mode. */
add a4, pc, #1 /* Get the address of the Thumb block. */
bx a4 /* Go there and start Thumb decoding. */
Index: libgloss/arm/swi.h
===================================================================
RCS file: /var/cvsroot/src-cvs/src/libgloss/arm/swi.h,v
retrieving revision 1.1
diff -u -p -r1.1 swi.h
--- libgloss/arm/swi.h 9 Jun 2004 19:06:50 -0000 1.1
+++ libgloss/arm/swi.h 7 Feb 2006 16:44:39 -0000
@@ -33,6 +33,14 @@
#else
#define AngelSWI AngelSWI_ARM
#endif
+/* For Thumb-2 code use the BKPT instruction instead of SWI. */
+#ifdef __thumb2__
+#define AngelSWIInsn "bkpt"
+#define AngelSWIAsm bkpt
+#else
+#define AngelSWIInsn "swi"
+#define AngelSWIAsm swi
+#endif
/* The reason codes: */
#define AngelSWI_Reason_Open 0x01
Index: libgloss/arm/syscalls.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/libgloss/arm/syscalls.c,v
retrieving revision 1.8
diff -u -p -r1.8 syscalls.c
--- libgloss/arm/syscalls.c 30 Nov 2005 23:37:14 -0000 1.8
+++ libgloss/arm/syscalls.c 7 Feb 2006 16:34:58 -0000
@@ -99,7 +99,7 @@ static inline int
do_AngelSWI (int reason, void * arg)
{
int value;
- asm volatile ("mov r0, %1; mov r1, %2; swi %a3; mov %0, r0"
+ asm volatile ("mov r0, %1; mov r1, %2; " AngelSWIInsn " %a3; mov %0, r0"
: "=r" (value) /* Outputs */
: "r" (reason), "r" (arg), "i" (AngelSWI) /* Inputs */
: "r0", "r1", "r2", "r3", "ip", "lr", "memory", "cc"
Index: libgloss/arm/trap.S
===================================================================
RCS file: /var/cvsroot/src-cvs/src/libgloss/arm/trap.S,v
retrieving revision 1.1
diff -u -p -r1.1 trap.S
--- libgloss/arm/trap.S 9 Jun 2004 19:06:50 -0000 1.1
+++ libgloss/arm/trap.S 3 Feb 2006 17:42:28 -0000
@@ -1,4 +1,5 @@
/* Run-time exception support */
+#if !defined(__thumb2__)
#include "swi.h"
/* .text is used instead of .section .text so it works with arm-aout too. */
@@ -91,3 +92,4 @@ __rt_stkovf_split_big:
@ We now know how much extra stack the function requires.
@ Terminate the program for the moment:
swi SWI_Exit
+#endif
Index: newlib/libc/machine/arm/setjmp.S
===================================================================
RCS file: /var/cvsroot/src-cvs/src/newlib/libc/machine/arm/setjmp.S,v
retrieving revision 1.1
diff -u -p -r1.1 setjmp.S
--- newlib/libc/machine/arm/setjmp.S 9 Jun 2004 19:05:09 -0000 1.1
+++ newlib/libc/machine/arm/setjmp.S 2 Feb 2006 16:52:52 -0000
@@ -51,17 +51,39 @@
Function entry is much simpler. If we are compiling for the Thumb we
just switch into ARM mode and then drop through into the rest of the
function. The function exit code will take care of the restore to
- Thumb mode. */
+ Thumb mode.
+
+ For Thumb-2 do everything in Thumb mode. */
#ifdef __APCS_26__
#define RET movs pc, lr
+#elif defined(__thumb2__)
+#define RET bx lr
#else
#define RET tst lr, #1; \
moveq pc, lr ; \
.word 0xe12fff1e /* bx lr */
#endif
-#ifdef __thumb__
+#ifdef __thumb2__
+.macro COND where when
+ i\where \when
+.endm
+#else
+.macro COND where when
+.endm
+#endif
+
+#if defined(__thumb2__)
+.syntax unified
+.macro MODE
+ .thumb
+ .thumb_func
+.endm
+.macro PROLOGUE name
+.endm
+
+#elif defined(__thumb__)
#define MODE .thumb_func
.macro PROLOGUE name
.code 16
@@ -70,7 +92,7 @@
.code 32
SYM (.arm_start_of.\name):
.endm
-#else
+#else /* Arm */
#define MODE .code 32
.macro PROLOGUE name
.endm
@@ -131,6 +153,9 @@ SYM (\name):
/* Put the return value into the integer result register.
But if it is zero then return 1 instead. */
movs a1, a2
+#ifdef __thumb2__
+ it eq
+#endif
moveq a1, #1
FUNC_END longjmp
Index: newlib/libc/sys/arm/crt0.S
===================================================================
RCS file: /var/cvsroot/src-cvs/src/newlib/libc/sys/arm/crt0.S,v
retrieving revision 1.11
diff -u -p -r1.11 crt0.S
--- newlib/libc/sys/arm/crt0.S 19 Jul 2005 15:14:16 -0000 1.11
+++ newlib/libc/sys/arm/crt0.S 7 Feb 2006 16:43:32 -0000
@@ -18,15 +18,26 @@
/* .text is used instead of .section .text so it works with arm-aout too. */
.text
+#if defined(__thumb2__)
+ .syntax unified
+ .thumb
+.macro FUNC_START name
+ .global \name
+ .thumb_func
+\name:
+.endm
+#else
.code 32
+.macro FUNC_START name
+ .global \name
+\name:
+.endm
+#endif
.align 0
- .global _mainCRTStartup
- .global _start
- .global start
-start:
-_start:
-_mainCRTStartup:
+ FUNC_START _mainCRTStartup
+ FUNC_START _start
+ FUNC_START start
#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
/* Annotation for EABI unwinding tables. */
.fnstart
@@ -45,7 +56,12 @@ _mainCRTStartup:
/* Issue Angel SWI to read stack info */
mov r0, #AngelSWI_Reason_HeapInfo
adr r1, .LC0 /* point at ptr to 4 words to receive data */
- swi AngelSWI_ARM /* We are always in ARM mode for startup */
+#if defined(__thumb2__)
+ bkpt AngelSWI
+#else
+ /* We are always in ARM mode for startup */
+ AngelSWIAsm AngelSWI_ARM
+#endif
ldr r0, .LC0 /* point at values read */
ldr sp, [r0, #8]
ldr sl, [r0, #12]
@@ -75,8 +91,8 @@ _mainCRTStartup:
sub a3, a3, a1 /* Third arg: length of block */
-#ifdef __thumb__ /* Enter Thumb mode.... */
-
+#if defined(__thumb__) && !defined(__thumb2__)
+ /* Enter Thumb mode.... */
add a4, pc, #1 /* Get the address of the Thumb block */
bx a4 /* Go there and start Thumb decoding */
@@ -100,7 +116,7 @@ __change_mode:
#else
mov r0, #AngelSWI_Reason_GetCmdLine
adr r1, .LC30 /* Space for command line */
- swi AngelSWI
+ AngelSWIAsm AngelSWI
ldr r1, .LC30
#endif
/* Parse string at r1 */
@@ -222,7 +238,7 @@ __change_mode:
bl FUNCTION (exit) /* Should not return. */
-#ifdef __thumb__
+#if defined(__thumb__) && !defined(__thumb2__)
/* Come out of Thumb mode. This code should be redundant. */
mov a4, pc
Index: newlib/libc/sys/arm/libcfunc.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/newlib/libc/sys/arm/libcfunc.c,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 libcfunc.c
--- newlib/libc/sys/arm/libcfunc.c 17 Feb 2000 19:39:49 -0000 1.1.1.1
+++ newlib/libc/sys/arm/libcfunc.c 7 Feb 2006 16:03:37 -0000
@@ -13,7 +13,7 @@ static inline int
do_AngelSWI (int reason, void * arg)
{
int value;
- asm volatile ("mov r0, %1; mov r1, %2; swi %a3; mov %0, r0"
+ asm volatile ("mov r0, %1; mov r1, %2; " AngelSWIInsn " %a3; mov %0, r0"
: "=r" (value) /* Outputs */
: "r" (reason), "r" (arg), "i" (AngelSWI) /* Inputs */
: "r0", "r1", "lr"
Index: newlib/libc/sys/arm/swi.h
===================================================================
RCS file: /var/cvsroot/src-cvs/src/newlib/libc/sys/arm/swi.h,v
retrieving revision 1.2
diff -u -p -r1.2 swi.h
--- newlib/libc/sys/arm/swi.h 21 Jun 2002 06:55:37 -0000 1.2
+++ newlib/libc/sys/arm/swi.h 7 Feb 2006 16:46:54 -0000
@@ -33,6 +33,14 @@
#else
#define AngelSWI AngelSWI_ARM
#endif
+/* For Thumb-2 code use the BKPT instruction instead of SWI. */
+#ifdef __thumb2__
+#define AngelSWIInsn "bkpt"
+#define AngelSWIAsm bkpt
+#else
+#define AngelSWIInsn "swi"
+#define AngelSWIAsm swi
+#endif
/* The reason codes: */
#define AngelSWI_Reason_Open 0x01
Index: newlib/libc/sys/arm/syscalls.c
===================================================================
RCS file: /var/cvsroot/src-cvs/src/newlib/libc/sys/arm/syscalls.c,v
retrieving revision 1.10
diff -u -p -r1.10 syscalls.c
--- newlib/libc/sys/arm/syscalls.c 8 Feb 2005 01:33:19 -0000 1.10
+++ newlib/libc/sys/arm/syscalls.c 7 Feb 2006 15:56:02 -0000
@@ -98,7 +98,7 @@ static inline int
do_AngelSWI (int reason, void * arg)
{
int value;
- asm volatile ("mov r0, %1; mov r1, %2; swi %a3; mov %0, r0"
+ asm volatile ("mov r0, %1; mov r1, %2; " AngelSWIInsn " %a3; mov %0, r0"
: "=r" (value) /* Outputs */
: "r" (reason), "r" (arg), "i" (AngelSWI) /* Inputs */
: "r0", "r1", "r2", "r3", "ip", "lr", "memory", "cc"
Index: newlib/libc/sys/arm/trap.S
===================================================================
RCS file: /var/cvsroot/src-cvs/src/newlib/libc/sys/arm/trap.S,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 trap.S
--- newlib/libc/sys/arm/trap.S 17 Feb 2000 19:39:49 -0000 1.1.1.1
+++ newlib/libc/sys/arm/trap.S 2 Feb 2006 15:31:27 -0000
@@ -1,4 +1,5 @@
/* Run-time exception support */
+#if !defined(__thumb2__)
#include "swi.h"
/* .text is used instead of .section .text so it works with arm-aout too. */
@@ -91,3 +92,4 @@ __rt_stkovf_split_big:
@ We now know how much extra stack the function requires.
@ Terminate the program for the moment:
swi SWI_Exit
+#endif