--- np2/i386c/ia32/exception.c	2004/02/20 16:09:04	1.12
+++ np2/i386c/ia32/exception.c	2008/03/22 04:03:07	1.21
@@ -1,4 +1,4 @@
-/*	$Id: exception.c,v 1.12 2004/02/20 16:09:04 monaka Exp $	*/
+/*	$Id: exception.c,v 1.21 2008/03/22 04:03:07 monaka Exp $	*/
 
 /*
  * Copyright (c) 2003 NONAKA Kimihiro
@@ -12,8 +12,6 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
@@ -72,6 +70,11 @@ exception(int num, int error_code)
 
 	__ASSERT((unsigned int)num < EXCEPTION_NUM);
 
+#if 0
+	iptrace_out();
+	debugwriteseg("execption.bin", &CPU_CS_DESC, CPU_PREV_EIP & 0xffff0000, 0x10000);
+#endif
+
 	VERBOSE(("exception: -------------------------------------------------------------- start"));
 	VERBOSE(("exception: %s, error_code = %x at %04x:%08x", exception_str[num], error_code, CPU_CS, CPU_PREV_EIP));
 	VERBOSE(("%s", cpu_reg2str()));
@@ -85,12 +88,13 @@ exception(int num, int error_code)
 
 	switch (num) {
 	case DE_EXCEPTION:	/* (F) 除算エラー */
+	case DB_EXCEPTION:	/* (F/T) デバッグ */
 	case BR_EXCEPTION:	/* (F) BOUND の範囲外 */
 	case UD_EXCEPTION:	/* (F) 無効オペコード */
 	case NM_EXCEPTION:	/* (F) デバイス使用不可 (FPU が無い) */
+	case MF_EXCEPTION:	/* (F) 浮動小数点エラー */
 		CPU_EIP = CPU_PREV_EIP;
 		/*FALLTHROUGH*/
-	case DB_EXCEPTION:	/* (F/T) デバッグ */
 	case NMI_EXCEPTION:	/* (I) NMI 割り込み */
 	case BP_EXCEPTION:	/* (T) ブレークポイント */
 	case OF_EXCEPTION:	/* (T) オーバーフロー */
@@ -102,11 +106,9 @@ exception(int num, int error_code)
 		error_code = 0;
 		break;
 
-#if CPU_FAMILY >= 4
 	case AC_EXCEPTION:	/* (F) アラインメントチェック (errcode: 0) */
 		error_code = 0;
 		/*FALLTHROUGH*/
-#endif
 	case TS_EXCEPTION:	/* (F) 無効 TSS (errcode) */
 	case NP_EXCEPTION:	/* (F) セグメント不在 (errcode) */
 	case SS_EXCEPTION:	/* (F) スタックセグメントフォルト (errcode) */
@@ -116,40 +118,36 @@ exception(int num, int error_code)
 		errorp = 1;
 		break;
 
-	case MF_EXCEPTION:	/* (F) 浮動小数点エラー */
-		CPU_EIP = CPU_PREV_EIP;
-		errorp = 0;
-		break;
-
-#if CPU_FAMILY >= 5
-	case MC_EXCEPTION:	/* (A) マシンチェック */
-		CPU_EIP = CPU_PREV_EIP;
-		errorp = 0;
-		break;
-#endif
-
-#if CPU_FAMILY >= 6
-	case XF_EXCEPTION:	/* (F) ストリーミング SIMD 拡張命令 */
-		CPU_EIP = CPU_PREV_EIP;
-		errorp = 0;
-		break;
-#endif
-
 	default:
 		ia32_panic("exception: unknown exception (%d)", num);
 		break;
 	}
 
+	if (CPU_STATSAVE.cpu_stat.backout_sp) {
+		VERBOSE(("exception: restore stack pointer."));
+		CPU_ESP = CPU_PREV_ESP;
+	}
+	CPU_STATSAVE.cpu_stat.backout_sp = 0;
+
 	if (CPU_STAT_EXCEPTION_COUNTER >= 2) {
 		if (dftable[exctype[CPU_STAT_PREV_EXCEPTION]][exctype[num]]) {
 			num = DF_EXCEPTION;
+			errorp = 1;
+			error_code = 0;
 		}
 	}
 	CPU_STAT_PREV_EXCEPTION = num;
 
 	VERBOSE(("exception: ---------------------------------------------------------------- end"));
 
-	INTERRUPT(num, 0, errorp, error_code);
+	interrupt(num, 0, errorp, error_code);
+#if defined(IA32_SUPPORT_DEBUG_REGISTER)
+	if (num != BP_EXCEPTION) {
+		if (CPU_INST_OP32) {
+			set_eflags(REAL_EFLAGREG|RF_FLAG, RF_FLAG);
+		}
+	}
+#endif
 	CPU_STAT_EXCEPTION_COUNTER_CLEAR();
 	siglongjmp(exec_1step_jmpbuf, 1);
 }
@@ -210,30 +208,33 @@ exception(int num, int error_code)
  * D          : ゲートのサイズ．0 = 16 bit, 1 = 32 bit
  */
 
-static void interrupt_task_gate(descriptor_t *gd, int softintp, int errorp, int error_code);
-static void interrupt_intr_or_trap(descriptor_t *gd, int softintp, int errorp, int error_code);
+static void interrupt_task_gate(const descriptor_t *gsdp, int intrtype, int errorp, int error_code);
+static void interrupt_intr_or_trap(const descriptor_t *gsdp, int intrtype, int errorp, int error_code);
 
 void
-interrupt(int num, int softintp, int errorp, int error_code)
+interrupt(int num, int intrtype, int errorp, int error_code)
 {
-	descriptor_t gd;
+	descriptor_t gsd;
 	UINT idt_idx;
 	UINT32 new_ip;
 	UINT16 new_cs;
+	int exc_errcode;
 
-	VERBOSE(("interrupt: num = 0x%02x, softintp = %s, errorp = %s, error_code = %08x", num, softintp ? "on" : "off", errorp ? "on" : "off", error_code));
+	VERBOSE(("interrupt: num = 0x%02x, intrtype = %s, errorp = %s, error_code = %08x", num, intrtype ? "on" : "off", errorp ? "on" : "off", error_code));
 
 	if (!CPU_STAT_PM) {
 		/* real mode */
+		CPU_WORKCLOCK(20);
+
 		idt_idx = num * 4;
 		if (idt_idx + 3 > CPU_IDTR_LIMIT) {
 			VERBOSE(("interrupt: real-mode IDTR limit check failure (idx = 0x%04x, limit = 0x%08x", idt_idx, CPU_IDTR_LIMIT));
 			EXCEPTION(GP_EXCEPTION, idt_idx + 2);
 		}
 
-		if (!softintp && CPU_STAT_HLT) {
+		if ((intrtype == INTR_TYPE_EXTINTR) && CPU_STAT_HLT) {
 			CPU_EIP++;
-			CPU_STAT_HLT = FALSE;
+			CPU_STAT_HLT = 0;
 		}
 
 		REGPUSH0(REAL_FLAGREG);
@@ -245,13 +246,13 @@ interrupt(int num, int softintp, int err
 
 		new_ip = cpu_memoryread_w(CPU_IDTR_BASE + idt_idx);
 		new_cs = cpu_memoryread_w(CPU_IDTR_BASE + idt_idx + 2);
-		CPU_SET_SEGREG(CPU_CS_INDEX, new_cs);
-		SET_EIP(new_ip);
-		CPU_WORKCLOCK(20);
+		LOAD_SEGREG(CPU_CS_INDEX, new_cs);
+		CPU_EIP = new_ip;
 	} else {
 		/* protected mode */
-		VERBOSE(("interrupt: -------------------------------------------------------------- start"));
+		CPU_WORKCLOCK(200);
 
+		VERBOSE(("interrupt: -------------------------------------------------------------- start"));
 		VERBOSE(("interrupt: old EIP = %04x:%08x, ESP = %04x:%08x", CPU_CS, CPU_EIP, CPU_SS, CPU_ESP));
 
 #if defined(DEBUG)
@@ -261,26 +262,33 @@ interrupt(int num, int softintp, int err
 		}
 #endif
 
-		/* VM86 && IOPL < 3 && interrupt cause == INTn */
-		if (CPU_STAT_VM86 && (CPU_STAT_IOPL < CPU_IOPL3) && (softintp == -1)) {
-			VERBOSE(("interrupt: VM86 && IOPL < 3 && INTn"));
-			EXCEPTION(GP_EXCEPTION, 0);
-		}
-
 		idt_idx = num * 8;
+		exc_errcode = idt_idx + 2;
+		if (intrtype == INTR_TYPE_EXTINTR)
+			exc_errcode++;
+
 		if (idt_idx + 7 > CPU_IDTR_LIMIT) {
 			VERBOSE(("interrupt: IDTR limit check failure (idx = 0x%04x, limit = 0x%08x", idt_idx, CPU_IDTR_LIMIT));
-			EXCEPTION(GP_EXCEPTION, idt_idx + 2 + !softintp);
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 		}
 
-		memset(&gd, 0, sizeof(gd));
-		load_descriptor(&gd, CPU_IDTR_BASE + idt_idx);
-		if (!gd.valid || !gd.p) {
+		/* load a gate descriptor from interrupt descriptor table */
+		memset(&gsd, 0, sizeof(gsd));
+		load_descriptor(&gsd, CPU_IDTR_BASE + idt_idx);
+		if (!SEG_IS_VALID(&gsd)) {
 			VERBOSE(("interrupt: gate descripter is invalid."));
-			EXCEPTION(GP_EXCEPTION, idt_idx + 2 + !softintp);
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
+		}
+		if (!SEG_IS_PRESENT(&gsd)) {
+			VERBOSE(("interrupt: gate descriptor is not present."));
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
+		}
+		if (!SEG_IS_SYSTEM(&gsd)) {
+			VERBOSE(("interrupt: gate descriptor is not system segment."));
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 		}
 
-		switch (gd.type) {
+		switch (gsd.type) {
 		case CPU_SYSDESC_TYPE_TASK:
 		case CPU_SYSDESC_TYPE_INTR_16:
 		case CPU_SYSDESC_TYPE_INTR_32:
@@ -289,36 +297,41 @@ interrupt(int num, int softintp, int err
 			break;
 
 		default:
-			VERBOSE(("interrupt: invalid gate type (%d)", gd.type));
-			EXCEPTION(GP_EXCEPTION, idt_idx + 2 + !softintp);
+			VERBOSE(("interrupt: invalid gate type (%d)", gsd.type));
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 			break;
 		}
 
+		if (gsd.dpl < CPU_STAT_CPL) {
+			VERBOSE(("interrupt: gate DPL(%d) < CPL(%d)", gsd.dpl, CPU_STAT_CPL));
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
+		}
+
 		/* 5.10.1.1. 例外／割り込みハンドラ・プロシージャの保護 */
-		if (softintp && (gd.dpl < CPU_STAT_CPL)) {
-			VERBOSE(("interrupt: softintp && DPL(%d) < CPL(%d)", gd.dpl, CPU_STAT_CPL));
-			EXCEPTION(GP_EXCEPTION, idt_idx + 2);
+		if ((intrtype != INTR_TYPE_EXTINTR) && (gsd.dpl < CPU_STAT_CPL)) {
+			VERBOSE(("interrupt: intrtype && DPL(%d) < CPL(%d)", gsd.dpl, CPU_STAT_CPL));
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 		}
 
-		if (!softintp && CPU_STAT_HLT) {
+		if (!intrtype && CPU_STAT_HLT) {
 			CPU_EIP++;
-			CPU_STAT_HLT = FALSE;
+			CPU_STAT_HLT = 0;
 		}
 
-		switch (gd.type) {
+		switch (gsd.type) {
 		case CPU_SYSDESC_TYPE_TASK:
-			interrupt_task_gate(&gd, softintp, errorp, error_code);
+			interrupt_task_gate(&gsd, intrtype, errorp, error_code);
 			break;
 
 		case CPU_SYSDESC_TYPE_INTR_16:
 		case CPU_SYSDESC_TYPE_INTR_32:
 		case CPU_SYSDESC_TYPE_TRAP_16:
 		case CPU_SYSDESC_TYPE_TRAP_32:
-			interrupt_intr_or_trap(&gd, softintp, errorp, error_code);
+			interrupt_intr_or_trap(&gsd, intrtype, errorp, error_code);
 			break;
 
 		default:
-			EXCEPTION(GP_EXCEPTION, idt_idx + 2 + !softintp);
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 			break;
 		}
 
@@ -327,18 +340,18 @@ interrupt(int num, int softintp, int err
 }
 
 static void
-interrupt_task_gate(descriptor_t *gd, int softintp, int errorp, int error_code)
+interrupt_task_gate(const descriptor_t *gsdp, int intrtype, int errorp, int error_code)
 {
 	selector_t task_sel;
 	int rv;
 
 	VERBOSE(("interrupt: TASK-GATE"));
 
-	(void)softintp;
+	(void)intrtype;
 
-	rv = parse_selector(&task_sel, gd->u.gate.selector);
-	if (rv < 0 || task_sel.ldt) {
-		VERBOSE(("interrupt: parse_selector (selector = %04x, rv = %d, %cDT)", gd->u.gate.selector, rv, task_sel.ldt ? 'L' : 'G'));
+	rv = parse_selector(&task_sel, gsdp->u.gate.selector);
+	if (rv < 0 || task_sel.ldt || !SEG_IS_SYSTEM(&task_sel.desc)) {
+		VERBOSE(("interrupt: parse_selector (selector = %04x, rv = %d, %cDT, type = %s)", gsdp->u.gate.selector, rv, task_sel.ldt ? 'L' : 'G', task_sel.desc.s ? "code/data" : "system"));
 		EXCEPTION(TS_EXCEPTION, task_sel.idx);
 	}
 
@@ -372,7 +385,7 @@ interrupt_task_gate(descriptor_t *gd, in
 }
 
 static void
-interrupt_intr_or_trap(descriptor_t *gd, int softintp, int errorp, int error_code)
+interrupt_intr_or_trap(const descriptor_t *gsdp, int intrtype, int errorp, int error_code)
 {
 	selector_t cs_sel, ss_sel;
 	UINT stacksize;
@@ -383,124 +396,134 @@ interrupt_intr_or_trap(descriptor_t *gd,
 	UINT32 new_ip, new_sp;
 	UINT32 old_ip, old_sp;
 	UINT16 old_cs, old_ss, new_ss;
+	int exc_errcode;
 	int rv; 
 
-	new_ip = gd->u.gate.offset;
+	new_ip = gsdp->u.gate.offset;
 	old_ss = CPU_SS;
 	old_cs = CPU_CS;
 	old_ip = CPU_EIP;
 	old_sp = CPU_ESP;
-	new_flags = old_flags = REAL_EFLAGREG;
+	old_flags = REAL_EFLAGREG;
+	new_flags = REAL_EFLAGREG & ~(T_FLAG|RF_FLAG|NT_FLAG|VM_FLAG);
+	mask = T_FLAG|RF_FLAG|NT_FLAG|VM_FLAG;
 
-	switch (gd->type) {
+	switch (gsdp->type) {
 	case CPU_SYSDESC_TYPE_INTR_16:
 	case CPU_SYSDESC_TYPE_INTR_32:
 		VERBOSE(("interrupt: INTERRUPT-GATE"));
 		new_flags &= ~I_FLAG;
-		mask = I_FLAG;
+		mask |= I_FLAG;
 		break;
 
 	case CPU_SYSDESC_TYPE_TRAP_16:
 	case CPU_SYSDESC_TYPE_TRAP_32:
 		VERBOSE(("interrupt: TRAP-GATE"));
+		break;
 
 	default:
-		mask = 0;
+		ia32_panic("interrupt: gate descriptor type is invalid (type = %d)", gsdp->type);
 		break;
 	}
-	new_flags &= ~(T_FLAG|RF_FLAG|NT_FLAG|VM_FLAG);
-	mask |= T_FLAG|RF_FLAG|NT_FLAG|VM_FLAG;
 
-	rv = parse_selector(&cs_sel, gd->u.gate.selector);
+	exc_errcode = cs_sel.idx;
+	if (intrtype == INTR_TYPE_EXTINTR)
+		exc_errcode++;
+
+	rv = parse_selector(&cs_sel, gsdp->u.gate.selector);
 	if (rv < 0) {
-		VERBOSE(("interrupt: parse_selector (selector = %04x, rv = %d)", gd->u.gate.selector, rv));
-		EXCEPTION(GP_EXCEPTION, cs_sel.idx + !softintp);
+		VERBOSE(("interrupt: parse_selector (selector = %04x, rv = %d)", gsdp->u.gate.selector, rv));
+		EXCEPTION(GP_EXCEPTION, exc_errcode);
 	}
 
 	/* check segment type */
-	if (!cs_sel.desc.s) {
+	if (SEG_IS_SYSTEM(&cs_sel.desc)) {
 		VERBOSE(("interrupt: code segment is system segment"));
-		EXCEPTION(GP_EXCEPTION, cs_sel.idx + !softintp);
+		EXCEPTION(GP_EXCEPTION, exc_errcode);
 	}
-	if (!cs_sel.desc.u.seg.c) {
+	if (SEG_IS_DATA(&cs_sel.desc)) {
 		VERBOSE(("interrupt: code segment is data segment"));
-		EXCEPTION(GP_EXCEPTION, cs_sel.idx + !softintp);
+		EXCEPTION(GP_EXCEPTION, exc_errcode);
 	}
 
 	/* check privilege level */
 	if (cs_sel.desc.dpl > CPU_STAT_CPL) {
 		VERBOSE(("interrupt: DPL(%d) > CPL(%d)", cs_sel.desc.dpl, CPU_STAT_CPL));
-		EXCEPTION(GP_EXCEPTION, cs_sel.idx + !softintp);
+		EXCEPTION(GP_EXCEPTION, exc_errcode);
 	}
 
 	/* not present */
 	if (selector_is_not_present(&cs_sel)) {
 		VERBOSE(("interrupt: selector is not present"));
-		EXCEPTION(NP_EXCEPTION, cs_sel.idx + !softintp);
+		EXCEPTION(NP_EXCEPTION, exc_errcode);
 	}
 
-	if (!cs_sel.desc.u.seg.ec
-	 && (cs_sel.desc.dpl < CPU_STAT_CPL)) {
+	if (!SEG_IS_CONFORMING_CODE(&cs_sel.desc) && (cs_sel.desc.dpl < CPU_STAT_CPL)) {
+		stacksize = errorp ? 12 : 10;
 		if (!CPU_STAT_VM86) {
 			VERBOSE(("interrupt: INTER-PRIVILEGE-LEVEL-INTERRUPT"));
-			stacksize = errorp ? 12 : 10;
 		} else {
 			/* VM86 */
+			VERBOSE(("interrupt: INTERRUPT-FROM-VIRTUAL-8086-MODE"));
 			if (cs_sel.desc.dpl != 0) {
 				/* 16.3.1.1 */
 				VERBOSE(("interrupt: DPL[CS](%d) != 0", cs_sel.desc.dpl));
-				EXCEPTION(GP_EXCEPTION, cs_sel.idx);
+				EXCEPTION(GP_EXCEPTION, exc_errcode);
 			}
-			VERBOSE(("interrupt: INTERRUPT-FROM-VIRTUAL-8086-MODE"));
-			stacksize = errorp ? 20 : 18;
+			stacksize += 8;
 		}
-		switch (gd->type) {
-		case CPU_SYSDESC_TYPE_INTR_32:
-		case CPU_SYSDESC_TYPE_TRAP_32:
+		if (gsdp->type & CPU_SYSDESC_TYPE_32BIT) {
 			stacksize *= 2;
-			break;
 		}
 
+		/* get stack pointer from TSS */
 		get_stack_pointer_from_tss(cs_sel.desc.dpl, &new_ss, &new_sp);
 
+		/* parse stack segment descriptor */
 		rv = parse_selector(&ss_sel, new_ss);
+
+		/* update exception error code */
+		exc_errcode = ss_sel.idx;
+		if (intrtype == INTR_TYPE_EXTINTR)
+			exc_errcode++;
+
 		if (rv < 0) {
 			VERBOSE(("interrupt: parse_selector (selector = %04x, rv = %d)", new_ss, rv));
-			EXCEPTION(TS_EXCEPTION, ss_sel.idx + !softintp);
+			EXCEPTION(TS_EXCEPTION, exc_errcode);
 		}
 
 		/* check privilege level */
 		if (ss_sel.rpl != cs_sel.desc.dpl) {
-			VERBOSE(("interrupt: RPL[SS](%d) != DPL[CS](%d)", ss_sel.rpl, cs_sel.desc.dpl));
-			EXCEPTION(TS_EXCEPTION, ss_sel.idx + !softintp);
+			VERBOSE(("interrupt: selector RPL[SS](%d) != DPL[CS](%d)", ss_sel.rpl, cs_sel.desc.dpl));
+			EXCEPTION(TS_EXCEPTION, exc_errcode);
 		}
 		if (ss_sel.desc.dpl != cs_sel.desc.dpl) {
-			VERBOSE(("interrupt: DPL[SS](%d) != DPL[CS](%d)", ss_sel.desc.dpl, cs_sel.desc.dpl));
-			EXCEPTION(TS_EXCEPTION, ss_sel.idx + !softintp);
+			VERBOSE(("interrupt: descriptor DPL[SS](%d) != DPL[CS](%d)", ss_sel.desc.dpl, cs_sel.desc.dpl));
+			EXCEPTION(TS_EXCEPTION, exc_errcode);
 		}
 
-		/* check segment type */
-		if (!ss_sel.desc.s) {
+		/* stack segment must be writable data segment. */
+		if (SEG_IS_SYSTEM(&ss_sel.desc)) {
 			VERBOSE(("interrupt: stack segment is system segment"));
-			EXCEPTION(TS_EXCEPTION, ss_sel.idx + !softintp);
+			EXCEPTION(TS_EXCEPTION, exc_errcode);
 		}
-		if (ss_sel.desc.u.seg.c) {
+		if (SEG_IS_CODE(&ss_sel.desc)) {
 			VERBOSE(("interrupt: stack segment is code segment"));
-			EXCEPTION(TS_EXCEPTION, ss_sel.idx + !softintp);
+			EXCEPTION(TS_EXCEPTION, exc_errcode);
 		}
-		if (!ss_sel.desc.u.seg.wr) {
+		if (!SEG_IS_WRITABLE_DATA(&ss_sel.desc)) {
 			VERBOSE(("interrupt: stack segment is read-only data segment"));
-			EXCEPTION(TS_EXCEPTION, ss_sel.idx + !softintp);
+			EXCEPTION(TS_EXCEPTION, exc_errcode);
 		}
 
 		/* not present */
 		if (selector_is_not_present(&ss_sel)) {
 			VERBOSE(("interrupt: selector is not present"));
-			EXCEPTION(SS_EXCEPTION, ss_sel.idx + !softintp);
+			EXCEPTION(SS_EXCEPTION, exc_errcode);
 		}
 
 		/* check stack room size */
-		CHECK_STACK_PUSH(&ss_sel.desc, new_sp, stacksize);
+		cpu_stack_push_check(ss_sel.idx, &ss_sel.desc, new_sp, stacksize);
 
 		/* out of range */
 		if (new_ip > cs_sel.desc.u.seg.limit) {
@@ -512,24 +535,22 @@ interrupt_intr_or_trap(descriptor_t *gd,
 		CPU_ESP = new_sp;
 
 		load_cs(cs_sel.selector, &cs_sel.desc, cs_sel.desc.dpl);
-		SET_EIP(new_ip);
+		CPU_EIP = new_ip;
 
-		switch (gd->type) {
-		case CPU_SYSDESC_TYPE_INTR_32:
-		case CPU_SYSDESC_TYPE_TRAP_32:
+		if (gsdp->type & CPU_SYSDESC_TYPE_32BIT) {
 			if (CPU_STAT_VM86) {
 				PUSH0_32(CPU_GS);
 				PUSH0_32(CPU_FS);
 				PUSH0_32(CPU_DS);
 				PUSH0_32(CPU_ES);
 
-				CPU_SET_SEGREG(CPU_GS_INDEX, 0);
+				LOAD_SEGREG(CPU_GS_INDEX, 0);
 				CPU_STAT_SREG(CPU_GS_INDEX).valid = 0;
-				CPU_SET_SEGREG(CPU_FS_INDEX, 0);
+				LOAD_SEGREG(CPU_FS_INDEX, 0);
 				CPU_STAT_SREG(CPU_FS_INDEX).valid = 0;
-				CPU_SET_SEGREG(CPU_DS_INDEX, 0);
+				LOAD_SEGREG(CPU_DS_INDEX, 0);
 				CPU_STAT_SREG(CPU_DS_INDEX).valid = 0;
-				CPU_SET_SEGREG(CPU_ES_INDEX, 0);
+				LOAD_SEGREG(CPU_ES_INDEX, 0);
 				CPU_STAT_SREG(CPU_ES_INDEX).valid = 0;
 			}
 			PUSH0_32(old_ss);
@@ -540,10 +561,7 @@ interrupt_intr_or_trap(descriptor_t *gd,
 			if (errorp) {
 				PUSH0_32(error_code);
 			}
-			break;
-
-		case CPU_SYSDESC_TYPE_INTR_16:
-		case CPU_SYSDESC_TYPE_TRAP_16:
+		} else {
 			if (CPU_STAT_VM86) {
 				ia32_panic("interrupt: 16bit gate && VM86");
 			}
@@ -555,35 +573,31 @@ interrupt_intr_or_trap(descriptor_t *gd,
 			if (errorp) {
 				PUSH0_16(error_code);
 			}
-			break;
 		}
-
-		set_eflags(new_flags, mask);
 	} else {
 		if (CPU_STAT_VM86) {
 			VERBOSE(("interrupt: VM86"));
-			EXCEPTION(GP_EXCEPTION, cs_sel.idx + !softintp);
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 		}
-		if (!cs_sel.desc.u.seg.ec && (cs_sel.desc.dpl != CPU_STAT_CPL)) {
-			VERBOSE(("interrupt: NON-CONFORMING-CODE-SEGMENT(%s) and DPL[CS](%d) != CPL", cs_sel.desc.u.seg.ec ? "false" : "true", cs_sel.desc.dpl, CPU_STAT_CPL));
-			EXCEPTION(GP_EXCEPTION, cs_sel.idx + !softintp);
+		if (!SEG_IS_CONFORMING_CODE(&cs_sel.desc) && (cs_sel.desc.dpl != CPU_STAT_CPL)) {
+			VERBOSE(("interrupt: %sCONFORMING-CODE-SEGMENT(%s) && DPL[CS](%d) != CPL", SEG_IS_CONFORMING_CODE(&cs_sel.desc) ? "" : "NON-", cs_sel.desc.dpl, CPU_STAT_CPL));
+			EXCEPTION(GP_EXCEPTION, exc_errcode);
 		}
+
 		VERBOSE(("interrupt: INTRA-PRIVILEGE-LEVEL-INTERRUPT"));
 
 		stacksize = errorp ? 8 : 6;
-		switch (gd->type) {
-		case CPU_SYSDESC_TYPE_INTR_32:
-		case CPU_SYSDESC_TYPE_TRAP_32:
+		if (gsdp->type & CPU_SYSDESC_TYPE_32BIT) {
 			stacksize *= 2;
-			break;
 		}
 
+		/* check stack room size */
 		if (CPU_STAT_SS32) {
 			sp = CPU_ESP;
 		} else {
 			sp = CPU_SP;
 		}
-		CHECK_STACK_PUSH(&CPU_STAT_SREG(CPU_SS_INDEX), sp, stacksize);
+		SS_PUSH_CHECK(sp, stacksize);
 
 		/* out of range */
 		if (new_ip > cs_sel.desc.u.seg.limit) {
@@ -592,32 +606,25 @@ interrupt_intr_or_trap(descriptor_t *gd,
 		}
 
 		load_cs(cs_sel.selector, &cs_sel.desc, CPU_STAT_CPL);
-		SET_EIP(new_ip);
+		CPU_EIP = new_ip;
 
-		switch (gd->type) {
-		case CPU_SYSDESC_TYPE_INTR_32:
-		case CPU_SYSDESC_TYPE_TRAP_32:
+		if (gsdp->type & CPU_SYSDESC_TYPE_32BIT) {
 			PUSH0_32(old_flags);
 			PUSH0_32(old_cs);
 			PUSH0_32(old_ip);
 			if (errorp) {
 				PUSH0_32(error_code);
 			}
-			break;
-
-		case CPU_SYSDESC_TYPE_INTR_16:
-		case CPU_SYSDESC_TYPE_TRAP_16:
+		} else {
 			PUSH0_16(old_flags);
 			PUSH0_16(old_cs);
 			PUSH0_16(old_ip);
 			if (errorp) {
 				PUSH0_16(error_code);
 			}
-			break;
 		}
-
-		set_eflags(new_flags, mask);
 	}
+	set_eflags(new_flags, mask);
 
-	VERBOSE(("interrupt: new EIP = %04x:%08x, new ESP = %04x:%08x", CPU_CS, CPU_EIP, CPU_SS, CPU_ESP));
+	VERBOSE(("interrupt: new EIP = %04x:%08x, ESP = %04x:%08x", CPU_CS, CPU_EIP, CPU_SS, CPU_ESP));
 }