;Write assembly language code for all type of the conditional overgflow and signed
;program flow control instructions
TTL transfer
AREA Myprog, CODE, READONLY
ENTRY
EXPORT main
main
;Table1: Conditional branch instructions for overflow detections
;==============================================================================
;Required branch control Unsigned data Signed data
;==============================================================================
;If (overflow(R0 + R1)) then branch BCS label BVS label
;If (no_overflow(R0 + R1)) then branch BCC label BVC label
;If (overflow(R0 – R1)) then branch BCC label BVS label
;If (no_overflow(R0 – R1)) then branch BCS label BVC label
;==============================================================================
;Table2: Conditional branch instructions for positive or negative value detection
;==============================================================================
;Required branch control Unsigned data Signed data
;==============================================================================
;If (result >=0) then branch Not applicable BPL label
;If (result < 0) then branch Not applicable BMI label
;==============================================================================
;unsigned overflow detection/ carry flag based branch
LDR R6,=0xFFFFFFFF
LDR R5,=0x00000001
LOOP11 ADDS R6,R6,R5
; during first addition carry flag is set, ans is C=1 R6=0x00000000
; during second addition carry flag is reset, ans is C=0 R6=0x00000001
BCC LOOP10 ;branch if C=0
BCS LOOP11 ;branch if C=1
;above example peform the overflow for addition operations
;for subtraction you can do it by your own
;Signed overflow incorporate signed ov, carry and Signed flag
LOOP10
LDR R6,=0xFFFFFFFF
LDR R5,=0x80000000
LOOP12 ADDS R6,R6,R5
; during first addition sign change and ov flag is set, ans is N=0,C=1,ov=1 R6=0x7FFFFFFF
; during second addition sign changes and ov flag is reset, ans is N=1,C=0,ov=0 R6=0xFFFFFFFF
BVC LOOP13 ;branch if V=0
BCS LOOP15 ;branch if C=1
LOOP15 BPL LOOP16 ;branch if N=0
LOOP16 BVS LOOP12 ;branch if V=1
LOOP13 BCC LOOP14 ;branch if C=0
LOOP14 BMI done ;branch if N=1
done
SWI &11
END
Write assembly language code for all type of the conditional overgflow and signed program flow control instructions
Write assembly language code for all type of the conditional for value comparison operations
;Write assembly language code for all type of the conditional for value comparison operations
TTL transfer
AREA Myprog, CODE, READONLY
ENTRY
EXPORT main
main
;*****************************conditional instructions***************************
;Table: Conditional branch instructions for value comparison operations
;=============================================================================
;Required branch control Unsigned data Signed data
;=============================================================================
;If (R0 equal R1) then branch BEQ label BEQ label
;If (R0 not equal R1) then branch BNE label BNE label
;If (R0 > R1) then branch BHI label BGT label
;If (R0 >= R1) then branch BCS label/BHS label BGE label
;If (R0 < R1) then branch BCC label/BLO label BLT label
;If (R0 <= R1) then branch BLS label BLE label
;=============================================================================
MOVS R1,#3
MOVS R2,#3
MOVS R3,#4
;for signed and unsigned equ and Not equ
CMP R2, R1 ; compare the R2 with R1 and reflect the status in FLAGS
BEQ LOOP3 ;branch if R2 = R1
LOOP3 CMP R2,R3 ; compare the R2 with R3 and reflect the status in FLAGS
BNE LOOP4_1 ; branch if R2 != R3
;unsigned greater than/equal and less than/equal
LOOP4_1 MOVS R1,#5 ;Loop counter starting value is 5
LOOP4
ADDS R4, #1
CMP R1, R4
BLO LOOP5 ;branch if R1<R4/ R1 is lower than R4
SUBS R1, #1
BHI LOOP4 ;branch if R1 is higher than 1
LOOP5 MOVS R1,#6 ;Loop counter starting value is 6
ADDS R4, #1
CMP R1, R4
BLS LOOP6 ;branch if R1<= R4/ R1 lower than or same to R4
SUBS R1, #1
BHS LOOP5 ;branch if R1 is higher and same to 1
;signed greater than/equal and less than/equal
LOOP6 MOVS R1,#5 ;Loop counter starting value is 5
MOVS R4,#0 ;Set R4 to zero
LOOP7
ADDS R4, #1
CMP R1, R4
BLT LOOP8 ;branch if R1<R4
SUBS R1, #1
BGT LOOP7 ;branch if R1>1
LOOP8 MOVS R1,#6 ;Loop counter starting value is 3
ADDS R4, #1
CMP R1, R4
BLE done ; branch if R1<=R4
SUBS R1, #1
BGE LOOP8 ; branch if R1>=1
done
SWI &11
END