58 lines
1.6 KiB
Plaintext
58 lines
1.6 KiB
Plaintext
; --------------------------------------
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; zasm: assemble "loader.z80"
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; date: 2021-01-14 02:43:53
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; --------------------------------------
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;Retrieves CP/M from disk and loads it in memory starting at E400h
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;Uses calls to ROM subroutine for disk read.
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;Reads track 0, sectors 2 to 26, then track 1, sectors 1 to 25
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;This program is loaded into LBA sector 0 of disk, read to loc. 0800h by ROM disk_read subroutine, and executed.
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#target bin
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#code _HOME, 0x1100
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hstbuf equ 0x1200 ;will put 256-byte raw sector here
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disk_read equ 0x0296 ;subroutine in 2K ROM
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cpm equ 0xFA00 ;CP/M cold start entry in BIOS
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main:
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ld c,1 ;LBA bits 0 to 7
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ld b,0 ;LBA bits 8 to 15
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ld e,0 ;LBA bits 16 to 23
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ld hl,0xE400 ; Memory address -- start of CCP
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loop:
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call disk_read ;subroutine in ROM
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ld a,c
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cp 50
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jp z,done
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inc a
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ld c,a
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jp loop
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done:
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out (1),a ;switch memory config to all-RAM
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jp cpm ;to BIOS cold start entry
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; +++ segments +++
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#CODE _HOME = $1100 = 4352, size = $001C = 28
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; +++ global symbols +++
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_HOME = $1100 = 4352 _HOME loader.z80:6 (unused)
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_HOME_end = $111C = 4380 _HOME loader.z80:6 (unused)
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_HOME_size = $001C = 28 _HOME loader.z80:6 (unused)
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cpm = $FA00 = 64000 _HOME loader.z80:11
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disk_read = $0296 = 662 _HOME loader.z80:10
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done = $1117 = 4375 _HOME loader.z80:28
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hstbuf = $1200 = 4608 _HOME loader.z80:9 (unused)
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loop = $1109 = 4361 _HOME loader.z80:19
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main = $1100 = 4352 _HOME loader.z80:13 (unused)
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total time: 0.0002 sec.
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no errors
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