| Line 12... |
Line 12... |
; + - (x= 22,y=-4,R0=-5,R1= 2)
|
; + - (x= 22,y=-4,R0=-5,R1= 2)
|
; - - (x=-22,y=-4,R0= 5,R1=-2)
|
; - - (x=-22,y=-4,R0= 5,R1=-2)
|
;
|
;
|
;
|
;
|
;
|
;
|
divs: ; Given R0,R1, computer R0 = R0/R1 and R1 = R0%R1 for signed R0,R1
|
lib_divs: ; Given R0,R1, computer R0 = R0/R1 and R1 = R0%R1 for signed R0,R1
|
SUB 2,SP
|
SUB 2,SP
|
; (stall)
|
STO R2,(SP)
|
STO R3,2(SP)
|
STO R3,2(SP)
|
;
|
;
|
CLR R3 ; Keep track of resulting sign in R2
|
CLR R3 ; Keep track of resulting sign in R2
|
TST -1,R0 ; Is R0 negative?
|
TST -1,R0 ; Is R0 negative?
|
MOV ret_div32s(PC),R2
|
MOV ret_div32s(PC),R2
|
| Line 27... |
Line 27... |
MOV.LT divu_divs_return(PC),R2
|
MOV.LT divu_divs_return(PC),R2
|
TST -1,R1 ; Is R1 negative?
|
TST -1,R1 ; Is R1 negative?
|
XOR.LT 1,R3 ; If so, result will be opposite sign of before
|
XOR.LT 1,R3 ; If so, result will be opposite sign of before
|
NEG.LT R1 ; Now we get R1=ABS(R1)
|
NEG.LT R1 ; Now we get R1=ABS(R1)
|
MOV.LT divu_divs_return(PC),R2
|
MOV.LT divu_divs_return(PC),R2
|
STO R2,1(SP)
|
BRA lib_divu ; Do our unsigned multiply
|
BRA divu ; Do our unsigned multiply
|
|
; JSR divu ; Do our unsigned multiply
|
; JSR divu ; Do our unsigned multiply
|
divu_divs_return:
|
divu_divs_return:
|
TST 1,R3 ; Check resulting sign
|
TST 1,R3 ; Check resulting sign
|
NEG.NE R0 ; Need to flip the sign of our result
|
NEG.NE R0 ; Need to flip the sign of our result
|
TST 2,R3 ; Now, if R1 was originally negative
|
TST 2,R3 ; Now, if R1 was originally negative
|
NEG.NE R1 ; Then negate R1
|
NEG.NE R1 ; Then negate R1
|
ret_div32s:
|
ret_div32s:
|
|
LOD (SP),R2
|
LOD 2(SP),R3
|
LOD 2(SP),R3
|
LOD 3(SP),R2
|
|
ADD 2,SP
|
ADD 2,SP
|
JMP R2
|
JMP R2
|
|
|
