20060303

1 files changed, 123 insertions, 0 deletions

diff --git a/os/cerf405/powerbreak.c b/os/cerf405/powerbreak.c
new file mode 100644
index 00000000..fc5970ef
--- /dev/null
+++ b/os/cerf405/powerbreak.c
@@ -0,0 +1,123 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"../port/error.h"
+#include	"ureg.h"
+
+extern int (*breakhandler)(Ureg *ur, Proc*);	/* trap.c */
+extern Instr BREAK;	/* trap.c */
+extern void portbreakinit(void);
+
+#define getop(i) ((i>>26)&0x3F)
+#define getxo(i) ((i>>1)&0x3FF)
+#define getbobi(i)	bo = (i>>21)&0x1f; bi = (i>>16)&0x1f; xx = (i>>11)&0x1f;
+
+void
+machbreakinit(void)
+{
+	portbreakinit();
+	breakhandler = breakhit;
+}
+
+Instr
+machinstr(ulong addr)
+{
+	if (addr < KTZERO)
+		error(Ebadarg);
+	return *(Instr*)addr;
+}
+
+void
+machbreakset(ulong addr)
+{
+	if (addr < KTZERO)
+		error(Ebadarg);
+	*(Instr*)addr = BREAK;
+	segflush((void*)addr, sizeof(Instr));
+}
+
+void
+machbreakclear(ulong addr, Instr i)
+{
+	if (addr < KTZERO)
+		error(Ebadarg);
+	*(Instr*)addr = i;
+	segflush((void*)addr, sizeof(Instr));
+}
+
+static int
+condok(Ureg *ur, ulong ir, int ctrok)
+{
+	int bo, bi, xx;
+	ulong ctrval;
+
+	ctrval = ur->ctr;
+	getbobi(ir);
+	if(xx)
+		return 0;	/* illegal */
+	if((bo & 0x4) == 0) {
+		if(!ctrok)
+			return 0;	/* illegal */
+		ctrval--;
+	}
+	if(bo & 0x4 || (ctrval!=0)^((bo>>1)&1)) {
+		if(bo & 0x10 || (((ur->cr & (1L<<(31-bi))!=0)==((bo>>3)&1))))
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Return the address of the instruction that will be executed after the
+ * instruction at ur->pc, accounting for current branch conditions.
+ */
+ulong
+machnextaddr(Ureg *ur)
+{
+	long imm;
+	ulong ir;
+
+	ir = *(ulong*)ur->pc;
+	switch(getop(ir)) {
+	case 18:	/* branch */
+		imm = ir & 0x03FFFFFC;
+		if(ir & 0x02000000)
+			imm |= 0xFC000000;	/* sign extended */
+		if((ir & 2) == 0)	/* relative address */
+			return ur->pc + imm;
+		return imm;
+			
+	case 16:	/* conditional branch */
+		if(condok(ur, ir&0xFFFF0000, 1)){
+			imm = ir & 0xFFFC;
+			if(ir & 0x08000)
+				imm |= 0xFFFF0000;	/* sign extended */
+			if((ir & 2) == 0)	/* relative address */
+				return ur->pc + imm;
+			return imm;
+		}
+		break;
+
+	case 19:	/* conditional branch to register */
+		switch(getxo(ir)){
+		case 528:	/* bcctr */
+			if(condok(ur, ir, 0))
+				return ur->ctr & ~3;
+			break;
+		case 16:	/* bclr */
+			if(condok(ur, ir, 1))
+				return ur->lr & ~3;
+			break;
+		}
+		break;
+	}
+	return ur->pc+4;	/* next instruction */
+}
+
+int
+isvalid_va(void *v)
+{
+	return (ulong)v >= KTZERO;
+}