Volex TTX2000 S Issue 1.2 | Routines |
Prev: 1C9B | Up: Map | Next: 1D66 |
Used by the routine at telesoftware_main.
|
||||
check_footer | 1D15 | LD DE,(page_receive_buffer_pointer) | Set HL to page_receive_buffer_pointer + 920 (row 23 of receive buffer). | |
1D19 | LD HL,$0398 | |||
1D1C | ADD HL,DE | |||
1D1D | LD A,$43 | If byte in column 0 is not $43 ('C') jump to check_footer_0. | ||
1D1F | CP (HL) | |||
1D20 | JP NZ,check_footer_0 | |||
1D23 | INC HL | If byte in column 1 is not $4F ('O') jump to check_footer_0. | ||
1D24 | LD A,$4F | |||
1D26 | CP (HL) | |||
1D27 | JR NZ,check_footer_0 | |||
1D29 | INC HL | If byte in column 2 is not $CD ('M' + parity) jump to check_footer_0. | ||
1D2A | LD A,$CD | |||
1D2C | CP (HL) | |||
1D2D | JP NZ,check_footer_0 | |||
1D30 | INC HL | If byte in column 3 is not $D0 ('P' + parity) jump to check_footer_0. | ||
1D31 | LD A,$D0 | |||
1D33 | CP (HL) | |||
1D34 | JR NZ,check_footer_0 | |||
1D36 | INC HL | If bit 6 of byte in column 5 is clear jump to check_footer_1. | ||
1D37 | INC HL | |||
1D38 | LD A,(HL) | |||
1D39 | BIT 6,A | |||
1D3B | JP Z,check_footer_1 | |||
1D3E | AND $3F | Store lower 6 bits (number of blocks) in D. | ||
1D40 | LD D,A | |||
1D41 | INC HL | If bit 6 of byte in column 7 is clear jump to check_footer_1. | ||
1D42 | INC HL | |||
1D43 | LD A,(HL) | |||
1D44 | BIT 6,A | |||
1D46 | JP Z,check_footer_1 | |||
1D49 | AND $3F | If lower 6 bits of byte (block number) is greater than or equal to D jump to check_footer_1. | ||
1D4B | CP D | |||
1D4C | JP P,check_footer_1 | |||
1D4F | LD E,A | Else set HL to $4800 + block number (offset in map of received blocks). | ||
1D50 | LD D,$00 | |||
1D52 | LD HL,$4800 | |||
1D55 | ADD HL,DE | |||
1D56 | LD A,(HL) | If byte at address in HL equals zero return $00, else jump to check_footer_2. | ||
1D57 | OR A | |||
1D58 | JP NZ,check_footer_2 | |||
1D5B | XOR A | Return $00 (ok). | ||
1D5C | RET | |||
check_footer_0 | 1D5D | LD A,$01 | Return $01 (not data). | |
1D5F | RET | |||
check_footer_1 | 1D60 | LD A,$02 | Return $02 (bad page). | |
1D62 | RET | |||
check_footer_2 | 1D63 | LD A,$03 | Return $03 (already received). | |
1D65 | RET |
Prev: 1C9B | Up: Map | Next: 1D66 |