Bootloader changes for ca1

bootloader/boot.S

@@ -1,23 +1,23 @@
 #include "board.h"
 
-.global boot68010
-.type boot68010, function
-boot68010:	// boot68010(vbr, ssp, pc)
+.section .start,"ax",@progbits
+.global boot_trap1
+.type boot_trap1, function
+boot_trap1:	// a0=vbr, a1=ssp, a2=pc
 	move.w  #0x2700, %sr
-	move.l  4(%sp), %a0  // vbr
 	movec.l %a0, %vbr
 	// fall through
 
-.global boot
-.type boot, function
-boot:	// boot(vbr, ssp, pc)
+.global boot_trap0
+.type boot_trap0, function
+boot_trap0:	// a1=ssp, a2=pc
 	move.w  #0x2700, %sr
-	move.l  12(%sp), %a0  // pc
-	move.l  8(%sp), %a1  // sp
+#if !NO_RESET_ON_BOOT
 	reset
+#endif
 #if HAS_BOOT_INC
 #	include "boot.inc"
 #endif
 	move.l  %a1, %sp
 	move.l  %a1, %usp
-	jmp     (%a0)
+	jmp     (%a2)

bootloader/boot.h

@@ -7,19 +7,31 @@
 #include <stddef.h>
 #include <inttypes.h>
 
-// Boot into a new location. Reinitializes everything just like the CPU does
-__attribute__((noreturn)) void boot(
-	uintptr_t vbr,
-	uintptr_t ssp,
-	uintptr_t pc
-);
+// Because a6boot can optionally run in user mode, we have to get supervisor
+// mode back before booting the user application. Do this by using traps to
+// perform the boot.
 
-// Boot into a new location, also moving the vector base register. Required
-// for 68010, will crash a 68000! Make sure to check the CPU identity.
-__attribute__((noreturn)) void boot68010(
-	uintptr_t vbr,
-	uintptr_t ssp,
-	uintptr_t pc
-);
+static inline __attribute__((noreturn)) void
+boot(uintptr_t vbr, uintptr_t ssp, uintptr_t pc)
+{
+	(void) vbr;
+	register uintptr_t a1_ssp asm("a1") = ssp;
+	register uintptr_t a2_pc  asm("a2") = pc;
+	asm volatile("trap #0" :: "r"(a1_ssp), "r"(a2_pc));
+	__builtin_unreachable();
+}
+
+static inline __attribute__((noreturn)) void
+boot68010(uintptr_t vbr, uintptr_t ssp, uintptr_t pc)
+{
+	register uintptr_t a0_vbr asm("a0") = vbr;
+	register uintptr_t a1_ssp asm("a1") = ssp;
+	register uintptr_t a2_pc  asm("a2") = pc;
+	asm volatile("trap #1" :: "r"(a0_vbr), "r"(a1_ssp), "r"(a2_pc));
+	__builtin_unreachable();
+}
+
+void boot_trap0(void);
+void boot_trap1(void);
 
 #endif // !defined(BOOT_H)

bootloader/bus_error_vecs.h

@@ -24,7 +24,23 @@ enum m68k_vec {
 	ZDIV_ERROR,
 	CHK_ERROR,
 	TRAPV_ERROR,
-	PRIV_ERROR
+	PRIV_ERROR,
+	TRAP0 = 32,
+	TRAP1,
+	TRAP2,
+	TRAP3,
+	TRAP4,
+	TRAP5,
+	TRAP6,
+	TRAP7,
+	TRAP8,
+	TRAP9,
+	TRAP10,
+	TRAP11,
+	TRAP12,
+	TRAP13,
+	TRAP14,
+	TRAP15,
 };
 
 // Last exception that occurred. User must clear.

bootloader/main.c

@@ -169,6 +169,9 @@ int main(void)
 	for (uint8_t i = 4; i != 0; i++)
 		vectab[i]   = &unexp_vec;
 
+	vectab[TRAP0] = boot_trap0;
+	vectab[TRAP1] = boot_trap1;
+
 	if (!_entry_prompt())
 		_boot(BOOT_APPLICATION, 0, 0);
 

bootloader/targets/ca1/board.h

@@ -42,11 +42,14 @@
 // the vector table writable.
 #define RUN_AS_USER 1
 
+// Whether the bootloader should not perform a peripheral reset when it boots
+// the application.
+#define NO_RESET_ON_BOOT 1
+
 // Whether certain commands should be included
 #define HAS_DEVICES 0
 #define HAS_PEEK    1
 #define HAS_POKE    1
-#define HAS_REBOOT  1  // Board package must define a reboot() function!
 
 #ifndef __ASSEMBLER__
 

bootloader/targets/ca1/meson.build

@@ -1,4 +1,4 @@
-board_sources = files('board.c', 'reboot.S')
+board_sources = files('board.c')
 board_depends = files('startup_pre.inc', 'boot.inc')
 
 a6boot_always_cpu = '68000'

bootloader/targets/ca1/reboot.S

@@ -1,9 +0,0 @@
-#include "board.h"
-
-.global reboot
-.type reboot,function
-reboot:
-	move.l  #__stack_top, %a0
-	move.l  %a0, %usp
-	move.l  %a0, %ssp
-	jmp     start