00B3 @ reset 00D2 @ beep 00FD @ kbdint 0040 ; 0x0f to NVR latch 0042 ; invert A (0xf0) 0043 ; 0xf0 to brightness 0045 ; zero A 0046 ; zero D, L, H 0049 ; next 2K ROM 004A ; store the current ROM # in B 004B ; show current ROM on LEDs 004D ; Checksum over 8 256B blocks 004F ; Rotate A left 0050 ; A <- A ^ memory 0051 ; next memory address 0052 ; ... repeat until end of block 0055 ; next block 0056 ; decrement block count 0057 ; ... repeat until end of chip 005A ; Check the value of the accumulator 005B ; If it's not zero, hang forever 005E ; Put the ROM # back in the accumulator 005F ; If it's not 4... 0061 ; repeat for the next ROM 0065 ; write 5 to LEDs (turns on L2 and L4) 0067 ; Test pattern: 0xaa 0069 ; 0x2c is the top of RAM on the basic board 006D ; flags buffer &= 0x02 : is AVO installed? 006F ; if bit 2 is not set, AVO is installed 0072 ; 0x40 is the top of RAM on the AVO 0074 ; load HL with top of RAM 0075 ; dec HL 0076 ; M <- 0 0078 ; dec HL 0079 ; a <- h 007A ; compare to 1f (top of ROM) 007C ; continue to zero if not at ROM 0080 ; read a byte of memory 0082 ; if it's zero, skip ahead 0088 ; err 008D ; err 0090 ; run test pattern through ram 0093 ; jump to 00a8 if ok 0099 ; err 009E ; ok 00A5 ; Hang if non-AVO memory 00B3 ; Repeat mem test with pattern 0x55 00BA ; zero scratch and screen mem 00BD ; Set a number of scratch values to fixed values 00C0 ; .... more memory initialization 00FE ; Read from keyboard port 0102 ; copy b <- a 0103 ; subtract 0x7c from a 0105 ; jump to 011a if a is a normal key 0108 ; otherwise h <- a 0109 ; h++ 010A ; a <- 0x10 0112 ; load keys flag addresss 0115 ; or in control bit 0116 ; store again 0117 ; jump to end to interrupt 011A ; load keys flag address 011F ; load key counter 0120 ; if overflow.. (>3 keys) 0122 ; discard keypress and end interrupt 0125 ; otherwise increment key counter 0126 ; load key address buffer? 0129 ; add key counter to address buffer 012C ; save key to address buffer 02A4 ; HL <- 0x204e (top of stack) 02A7 ; DE <- 0x0fb2 02AA ; B <- 0 02AC ; memset(0x204e,0,0xfb2) 02AF ; invert A 02B0 ; store A in 0x2104 02B3 ; HL <- 0x2004 02B6 ; *(0x2052) = 0x2004 02B9 ; HL <- 0x22d0 02BC ; *(20f6) = 0x22d0 02C0 ; 0x2140 = 0xe605 02C3 ; HL = 0x2000 02C6 ; DE = 0x02d9 02C9 ; B = 18 02CB ; copy 18 bytes from 0x02d9 to 0x2000 02CE ; HL = 0x3000 02D1 ; DE = 0x1000 02D4 ; B = 0xFF 02D6 ; Set all of attribute RAM to 0xFF and return 02EB ; HL = 0x0212 02EE ; Store 0x1202 at 0x212d 02F1 ; A = 0x35 02F3 ; 0x212c = 0x35 02F6 ; A = 1 02F8 ; 0x205b = 1 02FB ; 0x2176 = 1 02FE ; HL = 0x07ff 0301 ; store 0xff07 at 0x2149 0304 ; A = 2 0306 ; 0x2073 = 2 0309 ; A = 0xf7 030B ; 0x20fa = 0xf7 030E ; read flags buffer 0310 ; And it with 0x04 (check graphics flag) 0312 ; A=1 0314 ; if no graphics skip 0317 ; else store 1 in 0x2079 031A ; A = 0xff 031C ; 0x210e = 0xff 031F ; 0x21ba = 0xff 0322 ; H = 0x80 0324 ; L = 0x80 0325 ; Store 0x8080 at 0x20c0 038B ; Load memory at DE into accumulator 038C ; Store it at HL 038D ; HL++ 038E ; DE++ 038F ; B-- 0390 ; until B is zero 03CF ; Read from PUSART data 03DE ; Read from PUSART ctrl 08D4 ; subtract 5 from A and return if negative 08D7 ; load jump table at 8e5 08DA ; double a 08DE ; hl = X08e5 + 2A 08DF ; load DE from (HL) little-endian 08E3 ; zero A 08E4 ; jump to address 08E7 ; immediate return 08ED ; MYSTERY ADDRESS: this isn't even in AVO!!! 0A15 ; HL = 0x05e6 0A18 ; 0x2140 = 0xe605 1083 ; M <- B 1084 ; HL++ 1085 ; DE-- 1087 ; A = D | E 1088 ; repeat if A != 0 1493 ; Read flags buffer 1495 ; check if transmit buffer is empty 1497 ; if zero, return 1498 ; HL = 0x2144 149B ; Load from 2144 149C ; Check if zero 14A0 ; If not, A = 10 (else A is zero) 14A5 ; or bits from 0x21a5 14A9 ; or bits from 0x2145 14AB ; ... and 0x2146 14AD ; ... and 0x2147 14AE ; zero 0x2147 14B1 ; ... and 0x2148 14B2 ; zero 0x2148 14B4 ; Write to keyboard buffer 14B9 ; Increment what's at 0x2074 14BA ; load what's at 0x2077 14BD ; return if it's not zero 14BF ; A = 0x2065 14C5 ; return if [0x2065] | [0x2051] != 0 175B ; Initialize start of screen RAM and wipe attribute RAM to 0xff 175E ; B = 0x0a 1760 ; D = 1 1762 ; push B, D 1764 ; Display wait message 1767 ; pop D 1768 ; disable interrupts(???) 1769 ; HL = 0x217b 176C ; E = 0x33 176E ; C = 1 1770 ; A = 0 1771 ; 0x21ae = A 1774 ; A = C 1775 ; 0x21ad = A 1778 ; push D,H 177A ; A=D 177B ; or A 177C ; load A from HL 177D ; store it in 0x21af 1780 ; if A is 0 call X18ae 1783 ; call X18a3 1786 ; pop H,D 17BE ; DE = 0x17ec 17C1 ; B = 7 17C3 ; HL = 0x21cc 17C6 ; Initialize 0x21cc to Wait message 17C9 ; HL = 0xcc71 17CC ; retarget screen ram to display wait message 17DC ; DE = 0x17f3 17DF ; B = 11 17E1 ; store 18CD ; Write READ command to NVR latch 18DD ; Write 0x2fh (standby) to nvr latch 18E1 ; HL=X21d3 18E4 ; B= 14 -- we're reading 14 bits 18EF ; wait for NVR clock L 18F2 ; shft bit out of nvr 18F9 ; wait for NVR clock H 18FC ; read bit and store it in memory 1903 ; wait for NVR clock L 1907 ; read next bit 190A ; send standby 190E ; DE=0x21d3 1911 ; B = 14 1913 ; HL = 0 1917 ; load next char 1918 ; and with NVR data bit 191A ; rotate NVR bit to high bit 1924 ; Store the finished data in 21af and 21ae 1928 ; Load accumulator from 0x21ae -- (0x42) 192B ; B = 0xff 192D ; increment B 192E ; subtract 0x0a from accumulator 1930 ; repeat while accumulator is positive 1933 ; add 0x0a to accumulator 1935 ; HL = 0x21d3 1938 ; E = 0x23 193A ; D = 0x14 193D ; HL++ 193E ; D-- 193F ; repeat until D is zero 1942 ; Store 0x2f in 21e7 1944 ; HL = 0x21d3 1947 ; copy A to E 1948 ; clear D 194A ; add DE to HL -- calculate address of bit A 194B ; Store 0x22 in M 194D ; HL = 0x21d3 1950 ; A = 0x0a 1952 ; A = 0x0a + B 1964 ; Flags Buffer & C 1969 ; Return if B is negative