randu           LDR R0,seed
                LDR R1,magic
                MUL R0,R0,R1
                LDR R2,mask
                AND R0,R0,R2
                STR R0,seed
                MOV R0, R0 ASR #8 ; shift R0 right by 8 bits
                AND R0, R0, #0x3f  ; take the modulo by 64
                MOV PC,R14

; R1 is mine counter
; R2 will be for temp values
; R3 is board
; R4 will hold offset
; R5 will hold value at that location

generatestart   STMFD R13!, { R4, R5, R6, R7, R8, R14 }
                MOV R1,#0
                MOV R2,#66
                MOV R3,R0
                B generate

generate        CMP R1,#8
                BEQ endgenerate
                STMFD R13!, { R1 }
                BL randu
                LDMFD R13!, { R1 }
                MOV R4,#4
                MUL R4,R0,R4
                LDRB R5,[R4,R3]
                CMP R5,#66
                BEQ generate
                ADD R1,R1,#1
                MOV R2,#66
                STR R2,[R4,R3]
                ;initialise flag registers
                MOV R5,#0
                MOV R6,#0
                MOV R7,#0
                MOV R8,#0
                ;setting flags
                ;top
                CMP R0,#8
                MOVLT R5,#1
                ;left
                AND R4,R0,#7
                CMP R4,#0
                MOVEQ R6,#1
                ;bot
                CMP R0,#55
                MOVGT R7,#1
                ;right
                AND R4,R0,#7
                CMP R4,#7
                MOVEQ R8,#1

                B checktopleft

; R5 true if M on top
; R6 true if M on left
; R7 true if M on bot
; R8 true if M on right

checktopleft    CMP R5,#1
                BEQ checktopmid
                CMP R6,#1
                BEQ checktopmid
                MOV R4,R0
                SUB R4,R4,#9
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checktopmid
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checktopmid

checktopmid     CMP R5,#1
                BEQ checktopright
                MOV R4,R0
                SUB R4,R4,#8
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checktopright
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checktopright

checktopright   CMP R5,#1
                BEQ checkleftmid
                CMP R8,#1
                BEQ checkleftmid
                MOV R4,R0
                SUB R4,R4,#7
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checkleftmid
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checkleftmid

checkleftmid    CMP R6,#1
                BEQ checkrightmid
                MOV R4,R0
                SUB R4,R4,#1
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checkrightmid
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checkrightmid

checkrightmid   CMP R8,#1
                BEQ checkbotleft
                MOV R4,R0
                ADD R4,R4,#1
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checkbotleft
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checkbotleft

checkbotleft    CMP R7,#1
                BEQ checkbotmid
                CMP R6,#1
                BEQ checkbotmid
                MOV R4,R0
                ADD R4,R4,#7
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checkbotmid
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checkbotmid

checkbotmid     CMP R7,#1
                BEQ checkbotright
                MOV R4,R0
                ADD R4,R4,#8
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ checkbotright
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B checkbotright

checkbotright   CMP R7,#1
                BEQ generate
                CMP R8,#1
                BEQ generate
                MOV R4,R0
                ADD R4,R4,#9
                LDRB R2,[R3, R4 LSL #2]
                CMP R2,#66
                BEQ generate
                ADD R2,R2,#1
                STR R2,[R3, R4 LSL #2]
                B generate


endgenerate     LDMFD R13!, { R4, R5, R6, R7, R8, PC }
                MOV PC,R14