From: David Given <dg@cowlark.com>
Date: Sat, 27 Jun 2015 11:42:30 +0000 (+0200)
Subject: User processes start running; they can call back to the kernel via the
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=b9a20463deb461d4a18d6ada101aa4b8c4065c39;p=FUZIX.git

User processes start running; they can call back to the kernel via the
syscall interface.
---

diff --git a/Kernel/lowlevel-msp430x.c b/Kernel/lowlevel-msp430x.c
index f81ead25..80aca4b3 100644
--- a/Kernel/lowlevel-msp430x.c
+++ b/Kernel/lowlevel-msp430x.c
@@ -1,6 +1,7 @@
 #include <kernel.h>
 #include <kdata.h>
 #include <printf.h>
+#include <stdarg.h>
 #include "iomacros.h"
 #include "intrinsics.h"
 
@@ -11,7 +12,40 @@ __interrupt void interrupt_handler(void)
 
 void doexec(uaddr_t start_addr)
 {
-	kprintf("exec %lx\n", start_addr);
+	di();
+	udata.u_insys = 0;
+
+	asm volatile(
+		"mov %0, sp\n"
+		"eint\n"
+		"br %1\n"
+		:
+		: "g" (udata.u_isp),
+		  "g" (start_addr));
+}
+
+__attribute__ ((naked)) void unix_syscall_entry(void)
+{
+	asm volatile (
+		"mov.b r11, %0\n"
+		"mov r12, %1\n"
+		"mov r13, %2\n"
+		"mov r14, %3\n"
+		"mov r15, %4\n"
+		"jmp unix_syscall_main\n"
+		: "=m" (udata.u_callno),
+		  "=m" (udata.u_argn),
+		  "=m" (udata.u_argn1),
+		  "=m" (udata.u_argn2),
+		  "=m" (udata.u_argn3)
+		:
+	);
+}
+
+void unix_syscall_main(void)
+{
+	kprintf("syscall %d(%x, %x, %x, %x)!\n", udata.u_callno,
+		udata.u_argn, udata.u_argn1, udata.u_argn2, udata.u_argn3);
 	for (;;);
 }
 
diff --git a/Kernel/platform-msp430fr5969/crt0.S b/Kernel/platform-msp430fr5969/crt0.S
index 628eade5..a17f2390 100644
--- a/Kernel/platform-msp430fr5969/crt0.S
+++ b/Kernel/platform-msp430fr5969/crt0.S
@@ -91,6 +91,9 @@ proc irqrestore
 	bis.w r12, SR            ; Mask in saved value
 	reta
 
+.section ".syscall", "ax", @progbits
+	.long unix_syscall_entry
+
 .section "__interrupt_vector_reset", "ax", @progbits
 	.word __main
 .text
diff --git a/Kernel/platform-msp430fr5969/msp430fr5969.ld b/Kernel/platform-msp430fr5969/msp430fr5969.ld
index 03bc4853..ec61c9f8 100644
--- a/Kernel/platform-msp430fr5969/msp430fr5969.ld
+++ b/Kernel/platform-msp430fr5969/msp430fr5969.ld
@@ -226,6 +226,10 @@ SECTIONS
     KEEP (*(.dtors))
   } > LOROM
 
+  .syscall : {
+    KEEP (*(.syscall))
+  } > SYSCALL
+
   .lowtext : {
   	. = ALIGN(2);
     PROVIDE (_start = .);
diff --git a/Kernel/syscall_exec16.c b/Kernel/syscall_exec16.c
index 4837d4fa..78be29be 100644
--- a/Kernel/syscall_exec16.c
+++ b/Kernel/syscall_exec16.c
@@ -28,6 +28,10 @@ static int bload(inoptr i, uint16_t bl, uint16_t base, uint16_t len)
 			udata.u_offset = (off_t)blk << 9;
 			udata.u_count = 512;
 			udata.u_base = (uint8_t *)base;
+
+			/* This is necessary on the MSP430. Why??? */
+			*(uint8_t volatile*)base;
+
 			if (cdread(i->c_dev, 0) < 0) {
 				kputs("bload failed.\n");
 				return -1;