Routines
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5B21: Tape Loading
Used by the routine at TapeLoader.
Pull one tape block into the address and length set up by the caller.
Tape loading routine.
TapeLoading 5B21 SCF Set the carry flag to indicate "loading".
5B22 INC D This resets the Z flag (D cannot hold +FF.)
5B23 EX AF,AF' The A register holds +00 for a header and +FF for a block of data. The carry flag is reset for verifying and set for loading.
5B24 DEC D Put back D to its original value.
5B25 DI Disable interrupts while the tape loads, as the start of LD_BYTES would.
5B26 LD A,$0F Set the border to WHITE.
5B28 OUT ($FE),A
5B2A CALL $0562 Call LD_BYTES at 0562.
5B2D PUSH AF Remember whether the block loaded.
5B2E LD A,($5C48) A=*BORDCR.
5B31 AND %00111000 Keep the border colour (bits 3-5 of *BORDCR).
5B33 RRC A Move the border colour into the low three bits.
5B35 RRC A
5B37 RRC A
5B39 OUT ($FE),A Set border to the colour held by A.
5B3B LD A,$7F See whether SPACE is pressed.
5B3D IN A,($FE)
5B3F RRA
5B40 EI Re-enable interrupts, as the ROM does when its own load ends.
5B41 JP NC,$0000 Jump to START if the carry flag is not set.
5B44 POP AF Restore the load result from the stack (the carry flag is set when the block loaded).
5B45 RET C Return if the carry flag is set.
5B46 LD HL,($5C53) Write *PROG to *VARS.
5B49 LD ($5C4B),HL
5B4C LD (HL),$80 Write 80 to *PROG.
5B4E RST $08 Call ERROR_1.
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