pbio/platform/ev3: Copy only as much of the exception vector table as needed

Author: ArcaneNibble

lib/pbio/platform/ev3/exceptionhandler.S

@@ -1,6 +1,7 @@
 @ SPDX-License-Identifier: MPL-1.0
 @ Copyright (c) 2016 Tobias Schießl
-        .global ExceptionHandler
+        .global ExceptionHandlerStart
+        .global ExceptionHandlerEnd
         .global IRQHandler
         .global SWIHandler
         
@@ -20,17 +21,23 @@
 
         .code 32
 
+@ XXX this code will be copied (in one chunk) to the 0xffff0000 internal RAM,
+@ but the assembler/linker *do not know this*. Access to things outside of this file
+@ (such as the reset via calling Entry) needs to be written in a position-independent way.
+
 @ Default entry for all vectors except Reset is "B ExceptionHandler" so each interrupt would cause a reset
 @ Since I can only say that the IRQ Handler works, we leave the remaining ones as they are
-ExceptionHandler:
-        B Entry
-        B ExceptionHandler
+ExceptionHandlerStart:
+        ldr pc, =Entry
+        B ExceptionHandlerStart
         B SWIHandler
-        B ExceptionHandler
-        B ExceptionHandler
-        B ExceptionHandler
+        B ExceptionHandlerStart
+        B ExceptionHandlerStart
+        B ExceptionHandlerStart
         B IRQHandler
-        NOP @ Fall to FIQHandler
+        B FIQHandler
+
+.pool
         
 FIQHandler:
         STMFD    r13!, {r0-r7, lr}
@@ -104,4 +111,7 @@ loop:
 @
 @ End of the file
 @
+
+    .pool
+ExceptionHandlerEnd:
     .end

lib/pbio/platform/ev3/platform.c

@@ -394,16 +394,15 @@ const pbdrv_ioport_platform_data_t pbdrv_ioport_platform_data[PBDRV_CONFIG_IOPOR
 };
 
 // See exceptionhandler.S
-extern void ExceptionHandler(void);
+extern void ExceptionHandlerStart(void);
+extern void ExceptionHandlerEnd(void);
 
 void copy_vector_table(void) {
-    unsigned int *dest = (unsigned int *)0xFFFF0000;
-    unsigned int *addrExceptionHandler = (unsigned int *)ExceptionHandler;
-    int i = 1;
+    void *dest = (void *)0xFFFF0000;
+    void *addrExceptionHandler = (void *)ExceptionHandlerStart;
+    uint32_t sz = (uint32_t)ExceptionHandlerEnd - (uint32_t)ExceptionHandlerStart;
 
-    for (; i < 8 + 2048; ++i) {
-        dest[i] = addrExceptionHandler[i];
-    }
+    memcpy(dest, addrExceptionHandler, sz);
 }
 
 unsigned int EDMAVersionGet(void) {