From: Alan Cox <alan@linux.intel.com>
Date: Fri, 30 Jan 2015 00:25:41 +0000 (+0000)
Subject: 68000: base enabling pieces
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=2ec1e273ac87164a9b2fba623ffe1b4c510f8887;p=FUZIX.git

68000: base enabling pieces
---

diff --git a/Kernel/lowlevel-68000.S b/Kernel/lowlevel-68000.S
new file mode 100644
index 00000000..95d4fa78
--- /dev/null
+++ b/Kernel/lowlevel-68000.S
@@ -0,0 +1,225 @@
+/*
+ *	We do most of this in C on the 68000
+ */
+#include "kernel-68000.def"
+
+.mri 0
+		.globl di,ei,irqrestore
+		.globl doexec
+		.globl outstring,outstringhex,outcharhex,outa0hex
+.mri 1
+get_usp:	move.l	usp,a0
+		rts
+
+set_usp:	move.l 4(sp),a0
+		move.l a0,usp
+		rts
+
+/*
+ *	We don't currently have any fine grained IRQ control. We need to fix
+ *	that!
+ */
+di:
+		move.w sr,d0
+		and.w #$0700,d0
+		or.w #$0700,sr
+		rts
+
+ei:
+		and.w #$F8FF,sr
+		rts
+
+irqrestore:
+		move.w sr,d0
+		and.w #$F8FF,d0
+		or.w 4(sp),d0
+		move.w d0,sr
+		rts
+
+doexec:
+		move.l (sp)+,a0			; throw the return address
+		clr.w -(sp)			; set up the status register
+		move.l U_DATA__U_ISP,a0
+		move.l a0,usp			; set the user stack
+		moveq #0,d0			; wipe the registers
+		move.l d0,d1
+		move.l d0,d2
+		move.l d0,d3
+		move.l d0,d4
+		move.l d0,d5
+		move.l d0,d6
+		move.l d0,d7
+		move.l d0,a0
+		move.l d0,a1
+		move.l d0,a2
+		move.l d0,a3
+		move.l d0,a4
+		move.l d0,a5
+		move.l d0,a6
+		rte		; hit user space (and will enable interrupts)
+
+
+bus_error:	move.w #SIGBUS,-(sp)
+		bra sig_or_die
+addr_error:	move.w #SIGSEGV,-(sp)
+		bra sig_or_die
+illegal:	move.w #SIGILL,-(sp)
+		bra sig_or_die
+divzero:	move.w #SIGFPE,-(sp)
+		bra sig_or_die
+chk:		move.w #SIGFPE,-(sp)
+		bra sig_or_die
+trapv:		move.w #SIGFPE,-(sp)
+		bra sig_or_die
+priv:		move.w #SIGFPE,-(sp)
+		bra sig_or_die
+trace:		move.w #SIGTRAP,-(sp)
+		bra sig_or_die
+unimpa:		move.w #SIGFPE,-(sp)
+		bra sig_or_die
+unimpf:		move.w #SIGFPE,-(sp)
+		bra sig_or_die
+misctrap:	move.w #SIGILL,-(sp)
+		bra sig_or_die
+trap15:		move.w #SIGTRAP,-(sp)			; by convention
+		bra sig_or_die
+trap14:		movem.l a2-a6/d2-d7,-(sp)
+		move.b #1,d0
+		move.b d0,kernel_flag
+		; FIXME: EI per platform really
+		and.w #$F8FF,sr
+		bsr unix_syscall
+		; FIXME: signal handling in the C code or not ?
+	        or.w #$0700,sr
+		move.w U_DATA__U_ERROR,d1
+		bne sysc_err
+		move.w U_DATA__U_RETVAL,d0
+		movem.l (sp)+,a2-a6/d2-d7
+		rte
+sysc_err:	move.w #-1,d0
+		movem.l (sp)+,a2-a6/d2-d7
+		rte
+
+spurious:	movem.l a0-a6/d0-d7,-(sp)
+		move.l #strspurious,a0
+		bsr outstring
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+uninit:		movem.l a0-a6/d0-d7,-(sp)
+		move.l #struninitialized,a0
+		bsr outstring
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+strspurious:	asciz "spurious interrupt\n"
+struninitialized:
+		asciz "uninitialized interrupt\n"
+
+		.align 2
+;
+;	We do interrupts a bit differently - we use a single supervisor
+; stack per process, not an interrupt stack. As a result our signal handling
+; is a bit saner than 8bit.
+;
+#if 0
+_intvector1:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt1
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+_intvector2:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt3
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+_intvector3:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt3
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+_intvector4:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt4
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+_intvector5:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt5
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+_intvector6:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt6
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+_intvector7:	movem.l a0-a6/d0-d7,-(sp)
+		jsr _interrupt7
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+#endif
+sig_or_die:	
+		tst.b kernel_flag
+		beq sig_user
+		move.b (sp),d0
+		jsr outcharhex
+		lea panic_sig,a0
+		jsr outstring
+		lea panic_sig2,a0
+		jsr panic			; won't return
+panic_sig:	ascii ": signal in kernel mode."
+		byte 13,10
+panic_sig2:	asciz ": ksig"
+		.align 2
+
+sig_user:	movem.l a0-a6/d0-d7,-(sp)
+		move.l (U_DATA__U_PTAB),-(sp)
+		jsr ssig
+		adda #4,sp
+		; Do signal processing bit here if we return
+		movem.l (sp)+,a0-a6/d0-d7
+		rte
+
+;
+;	Debug
+;
+outstring:	move.b (a0)+,d0
+		beq outstrend
+		bsr outchar
+		bra outstring
+outstrend:	rts
+
+outstringhex:	move.b (a0)+,d0
+		beq outstrend
+		bsr outcharhex
+		bra outstringhex
+
+hexdigit:
+		add.b #48,d0
+		cmp.b #58,d0
+		bcs notltr
+		add.b #7,d0
+notltr:		bra outchar
+
+outa0hex:	move.l a0,d0
+		moveq #24,d1
+		lsr.l d1,d0
+		bsr outcharhex
+		move.l a0,d0
+		moveq #16,d1
+		lsr.l d1,d0
+		bsr outcharhex
+		move.l a0,d0
+		lsr.l #8,d0
+		bsr outcharhex
+		move.l a0,d0
+outcharhex:	move.w d0,-(sp)
+		lsr #4,d0
+		bsr hexdigit
+		move.w (sp),d0
+		bsr hexdigit
+		move.w (sp)+,d0
+		rts
+
+.area data
+kernel_flag:	byte 0
diff --git a/Kernel/usermem_std-68000.S b/Kernel/usermem_std-68000.S
new file mode 100644
index 00000000..8b960d61
--- /dev/null
+++ b/Kernel/usermem_std-68000.S
@@ -0,0 +1 @@
+/* Nothing to see.. */
\ No newline at end of file