Question

汇编程序求解，编译环境Freescale CodeWarrior，输入年月，求当月是几天，该怎么改，或是帮忙写一个，急等

MONTH ds.w 1
YEAR ds.w 1

main:
_Startup:
Entry:
LDS #__SEG_END_SSTACK ; initialize the stack pointer
CLI ; enable interrupts
LDAA #2
STAA MONTH
LDD #2008
STD YEAR

M_LEGTH LDAA #30
LDAB #2
CMPB MONTH
BEQ CALL2
BRA NEXT
CALL2 JSR FEBRARY
BRA Endlessloop
NEXT LDAB MONTH
CMPB #8
BLT ODDBIG
INCB
ODDBIG ANDB #1
ABA
Endlessloop:
BRA Endlessloop

FEBRARY: DECA
LDD YEAR
IDIV #400
XGDX
ANDX #FF
BEQ FINI

LDAB YEAR+1
ANDB #3
BEQ FIII
DECA

FIII: LDD YEAR
IDIV #100
ANDA #$FF
BNE FINI
DECA

FINI: RTS

Answer 1

ORG $2000
MONTH RMB 1
YEAR ds.w 1
ORG $2FF0
YEAR1 RMB 100

ORG $4000
main:
_Startup:
Entry:
LDS #$3000 ; initialize the stack pointer
CLI ; enable interrupts
LDAA #2
STAA MONTH
LDD #2100
STD YEAR

M_LEGTH LDAA #30
LDAB #2
CMPB MONTH
BEQ CALL2
BRA NEXT
CALL2 JSR FEBRARY
BRA Endlessloop
NEXT LDAB MONTH
CMPB #8
BLT ODDBIG
INCB
ODDBIG ANDB #1
ABA
Endlessloop:
BRA Endlessloop

FEBRARY: DECA
PSHA
LDD YEAR
LDX #400
IDIV
XGDX
ANDX #$FFFF
BEQ FINI

LDAB YEAR+1
ANDB #3
BEQ FIII
PULA
DECA
RTS

FIII: LDD YEAR
LDX #100
IDIV
ANDB #$FF
BNE FINI
PULA
DECA
RTS

FINI: PULA
RTS