5) The program of 8.34 executes, generating an interrupt for DECO. For figure 8.6, the entry to an exit from the trap handler, state the values in the following registers as four hexadecimal digits.

(a) X{8..15} after LDBX at FC52		(b) X after ASRX at FC69
(c) X after SUBX at FC6A			(d)PC after CALL at FC6E
(e) PC after RETTR at FC71


Figure 8.6:

											;********* Trap handler
				oldIR:	.EQUATE 9
				;
FC52	DB0009	trap:	LDBX	oldIR,s		;X < - trapped IR
FC55	B80028			CPBX	0x0028,i	;If X >= first nonunary trap opcode
FC58	1CFC67			BRGE	nonUnary	;	trap opcode is nonunary
				;
FC5B	880001	unary:	ANDX	0x0001,i	;Mask out all but the rightmost bit
FC5E	0B				ASLX				;Two bytes per address
FC5F	25FC63			CALL	unaryJT,x	;Call unary trap routine
FC62	02				RETR				;Return from trap
				;
FC63	FD6B	unaryJT:.ADDRSS	opcode26	;Address of NOP0 subroutine
FC65	FD6C			.ADDRSS opcode27	;Address of NOP1 subroutine
				;
FC67	0D		nonUnary:ASRX				;Trap opcode is nonunary
FC68	0D				 ASRX
FC69	0D				 ASRX
FC6A	780005			 SUBX	5,i			;Adjust so that NOP opcode = 0
FC6D	0B				 ASLX				;Two bytes per address
FC6E	25FC72			 CALL	nonUnJT,x	;Call nonunary trap routine
FC71	02		return:	 RETTR				;Return from trap
				;
FC72	FD6D	nonUnJT: .ADDRSS opcode28	;Address of NOP subroutine
FC74	FD77			 .ADDRSS opcode30	;Address of DECI subroutine
FC76	FEEB			 .ADDRSS opcode38	;Address of DECO subroutine
FC78	FF76			 .ADDRSS opcode40	;Address of HEXO subroutine
FC7A 	FFC2 			 .ADDRSS opcode48	;Address of STRO subroutine

---

Figure 8.34:

0000	120005			BR		main		;branch around data
0003	0000	num:	.BLOCK	2			;Global variable
0005	310003	main:	DECI	num,d		;Input decimal value
0008	390003			DECO	num,d		;Output decimal value
000B	D0000A			LDBA	'\n',i
000E	F1FC16			STBA	charOut,d	;Output message
0011	490015			STRO	msg,d
0014	00				STOP
0015	546861	msg:	.ASCII	"That's all. \x00"
		742773
		20616C
		6C2E00
0021					.END