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.adjusting the comments in ASM file for Part 1
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ped7g committed Feb 1, 2020
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Showing 1 changed file with 5 additions and 5 deletions.
10 changes: 5 additions & 5 deletions SpecBong.asm
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; SpecBong - tutorial-like project to load Layer2 image and move sprites
; © Peter Helcmanovsky, John McGibbitts 2020, license: https://opensource.org/licenses/MIT
;
; to build this ASM file I use https://github.com/z00m128/sjasmplus command:
; to build this ASM file we use https://github.com/z00m128/sjasmplus command:
; sjasmplus --fullpath --nologo --lst --lstlab --msg=war SpecBong.asm
; (this will also produce the listing file, so I can review the machine code generated
; (this will also produce the listing file, so we can review the machine code generated
; and addresses assigned to various symbols)
;
; to convert BMP to upside-down TGA I use ImageMagick "convert" command:
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; ^ it's the default mapping of assembler at assembling time, at runtime the NEXLOAD
; will set the default mapping the same way, but first 16k is ROM, not bank 7.

; $8000..BFFF is here Bank 2 (pages 4 and 5) -> I will put **all** code here
; $8000..BFFF is here Bank 2 (pages 4 and 5) -> we will put **all** code here
ORG $8000
start:
; break at start when running in CSpect with "-brk" option
break : nop : nop ; 2x"nop" after "break" to make real board survive "break" (= ld bc,0)

; disable interrupts, I will avoid using them to keep code simpler to understand
; disable interrupts, we will avoid using them to keep code simpler to understand
di
; make the Layer 2 visible and reset some registers (should be reset by NEXLOAD, but to be safe)
nextreg $69,$80 ; Layer 2 visible, ULA bank 5, Timex mode 0
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; pre-load the image pixel data from TGA file into memory (to store it in NEX file)
; the pixel data will be in 16k banks 9, 10, 11 (8k pages: 18, 19, .., 23)
; I will use the last page region $E000..$FFFF to map through all the pages and
; We will use the last page region $E000..$FFFF to map through all the pages and
; include the binary pixel data from the TGA file, using sjasmplus MMU directive

; map into last slot first Layer2 page (8ki page number = 16ki bank * 2 = 9*2 = 18)
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