Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Ch th CALL v RET Cỏc ch th gi th tc Ch th CALL: Chuyn iu khin n th tc b gi * Cỳ phỏp: [nhón] CALL <Tờn th tc> * Thc hin cỏc cụng vic: - Gim ni dung SP bi 2 - Ct ni dung IP vo Stack - a offset th tc b gi lờn IP Ch th RET: Chuyn iu khin tr v chng trỡnh gi t th tc b gi * Cỳ phỏp: [nhón] RET * Thc hin cỏc cụng vic: - Ly giỏ tr c ca IP t Stack np cho IP - Tng ni dung SP bi 2 Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Ch th CALL v RET Cỏc ch th gi th tc Vớ d: .CODE BEGIN PROC FAR CALL B10 ;gi th tc B10 MOV AX,4CH INT 21H BEGIN ENDP B10 PROC NEAR CALL C10 ;gi th tc C10 RET ;tr v v trớ gi B10 ENDP C10 PROC NEAR RET ;tr v v trớ gi C10 ENDP Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th logic - Cỏc ch th logic bao gm: AND, OR, XOR, TEST v NOT - Chc nng: Xúa hoc thit lp cỏc bit qun lý d liu ASCII cho cỏc mc ớch tớnh toỏn s hc - Cỳ phỏp tng quỏt: [nhón] Ch th (Thanh ghi/t nh),[Thanh ghi/t nh] * c trng: - AND: Hai bit tng ng l 1 thỡ kt qu l 1, ngc li kt qu l 0 - OR: Mt trong 2 bit (Hoc c 2 bit) l 1 thỡ kt qu l 1, ngc li kt qu l 0 - XOR: Hai bit tng ng khỏc nhau kt qu l 1, ngc li ging nhau thỡ kt qu l 0 - TEST: Tng t AND, nhng khụng lu kt qu - NOT: Kt qu l nghch o ca cỏc bit Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th logic Vớ d 1: AL=1100 0101, BH=0101 1100 Ch th AND: AND AL,BH ;AL=0100 0100 AND AL,00h ;AL=0000 0000 Ch th OR: OR BH,AL ;BH=1101 1101 Ch th XOR: XOR AL,AL ;AL=0000 0000 Ch th TEST: TEST BL,11000000b ;Kim tra cú bit no JNZ ;bờn trỏi khụng? TEST AL,00000001b ;Cú phi AL cha 1 JNZ ;s l Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th logic Vớ d 2: Vit chng trỡnh i ch thng thnh ch HOA Nhn xột: - Ch HOA t A Z cú giỏ tr ASCII t 41H 5AH - Ch thng t a z cú giỏ tr ASCII t 61H 7AH - S khỏc nhau duy nht: Bit th 5 (bng 0 - ch HOA v bng 1 - ch thng) Vớ d: Ch HOA Ch thng A= 0100 0001 a= 0110 0001 Z= 0101 1010 z= 0111 1010 Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th logic Vớ d 2: Vit chng trỡnh i ch thng thnh ch HOA Phng phỏp: - S dng ch th AND xúa i bit s 5 AH=0100 0001 AND AH,11011111b - Mó vớ d: ;nhp ký t MOV AH,1 INT 21h ;i t thng qua HOA AND AL,11011111b ;in ra mn hỡnh MOV AH,2 MOV DL,AL INT 21h Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th dch bit Cỳ phỏp: [nhón] Ch th dch (Thanh ghi/t nh), (CL) 1. Dch bit sang phi: - Ch th SHR: Dch phi logic, s dng bit 0 lm y - Ch th SAR: Dch phi s hc, s dng bit du lm y - Cỏc bit c nh ln lt t vo c CF - S dng cho phộp chia 2: Dch phi n bit tng ng chia 2 n bit Vớ d: Ch th SHR Ch th SAR MOV CL,3 MOV CL,3 MOV AL, B7h ;AL=1011 0111 MOV AL,B7h ;AL=1011 0111 SHR AL,1 ;AL=0101 1011 SAR AL,1 ;AL=1101 1011 SHR AL,CL ;AL=0000 1011 SAR AL,CL ;AL=1111 1011 Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th dch bit Cỳ phỏp: [nhón] Ch th dch (Thanh ghi/t nh), (CL) 2. Dch bit sang trỏi: - Ch th SHL,SAL: Dch trỏi logic, s dng bit 0 lm y v hot ng nh nhau. Cỏc bit c nh ln lt t vo c CF - S dng cho phộp nhõn 2: Dch trỏi n bit tng ng nhõn 2 n bit Vớ d: MOV CL,3 MOV AL,B7h ;AL=1011 0111 SHL AL,1 ;AL=0110 1110 SHL AL,CL ;AL=0111 0000 Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th quay bit Cỳ phỏp: [nhón] Ch th quay (Thanh ghi/t nh), (CL) 1. Quay bit sang phi: - Ch th ROR: Quay logic bit sang phi, bit c ch ra ngoi c a vo c CF v c dựng lm y - Ch th RCR: Quay s hc bit sang phi, bit c dch ra ngoi c a vo c CF v bit c CF c dựng lm y Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th quay bit Cỳ phỏp: [nhón] Ch th quay (Thanh ghi/t nh), (CL) 1. Quay bit sang phi: Vớ d 1: MOV CL,3 MOV BH,B7h ;BH=1011 0111 ROR BH,1 ;BH=1101 1011 ROR BH,CL ;BH=0111 1011 Vớ d 2: MOV CL,3 MOV BH,B7h ;BH=1011 0111 RCR BH,1 ;BH=0101 1011 (CF=0) ;BH=1101 1011 (CF=1) RCR BH,CL ;BH=1110 1011 (CF=0) ;BH=1111 1011 (CF=1) [...]...Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th quay bit Cỳ phỏp: [nhón] Ch th quay (Thanh ghi/t nh), (CL) 2 Quay bit sang trỏi: - Ch th ROL: Quay logic bit sang trỏi, bit c ch ra ngoi c a vo c CF v c dựng lm y - Ch th RCL: Quay s hc bit sang trỏi, bit c dch ra ngoi c a vo c CF v bit c CF c dựng lm y Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th quay bit... hc bit sang trỏi, bit c dch ra ngoi c a vo c CF v bit c CF c dựng lm y Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th quay bit Cỳ phỏp: [nhón] Ch th quay (Thanh ghi/t nh), (CL) 2 Quay bit sang trỏi: Vớ d 1: Vớ d 2: MOV MOV ROL ROL CL,3 BH,B7h BH,1 BH,CL MOV MOV RCL CL,3 BH,B7h BH,1 RCL BH,CL ;BH=1011 0111 ;BH=0110 1111 ;BH=0111 0111 ;BH=1011 0111 ;BH=0110 1110 (CF=0) ;BH=0110 1111 (CF=1) ;BH=0111 . JNZ ;s l Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th logic Vớ d 2: Vit chng trỡnh i ch thng thnh ch HOA Nhn xột: - Ch HOA t A Z cú giỏ tr ASCII t 41H 5AH - Ch thng t a z. RET ;tr v v trớ gi C10 ENDP Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th logic - Cỏc ch th logic bao gm: AND, OR, XOR, TEST v NOT - Chc nng: Xúa hoc thit lp cỏc bit qun lý. AH ,2 MOV DL,AL INT 21 h Chửụng 2: CAC CHặ THề LOGIC VAỉ ẹIEU KHIEN Cỏc ch th dch bit Cỳ phỏp: [nhón] Ch th dch (Thanh ghi/t nh), (CL) 1. Dch bit sang phi: - Ch th SHR: Dch phi logic,