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Reword README slightly.

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Piotr Fusik 2017-02-08 19:59:22 +01:00
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README.md
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@ -8,11 +8,10 @@ for [Atari 8-bit computers](http://en.wikipedia.org/wiki/Atari_8-bit_family).
Syntax
------
6502 assembly language is full of LDA, STA, LDA, STA sequences.
6502 assembly code is full of LDA, STA, LDA, STA sequences.
With xasm you can use MVA as a shortcut for an LDA/STA pair or even MWA for 16-bit transfers.
You can avoid defining labels when you need short jumps,
thanks to conditional skip and repeat pseudo-instructions.
You can put two instructions that share their argument in one line.
Short branches can be replaced with conditional skip and repeat pseudo-instructions.
You can use a pair of instructions with a shared argument.
These are just some of the features that help you program in a more concise way.
Let's look at typical 6502 code (which is also valid in xasm):
@ -45,13 +44,13 @@ Using xasm's features this code can be rewritten to:
do_line
ldy #39
mva:rpl pattern,y (ptr),y-
lda #40
lda #40
add:sta ptr
scc:inc ptr+1
dex:bne do_line
xasm syntax is based on 1990's Quick Assembler.
Write accumulator shifts as in `asl @`.
xasm syntax is an extension of Quick Assembler's (created in 1991 for Atari 8-bit).
Accumulator shifts should be written as in `asl @`.
Whitespace is important: it is required before the instruction
and disallowed in the operands, because it separates a comment from the operand, e.g.
@ -93,4 +92,4 @@ Links
* [cc65](http://cc65.github.io/cc65/) - C cross-compiler targeting 6502-based systems
* [MADS](http://mads.atari8.info/) - another 6502/65816 cross-assembler, partially supporting xasm's syntax
* [vim-xasm](https://github.com/lybrown/vim-xasm) - VIM syntax highlighting for xasm
* [WUDSN IDE](http://wudsn.com/) - Eclipse plugin, front-end to several 6502 cross-assemblers including xasm
* [WUDSN IDE](http://wudsn.com/) - Eclipse plugin, front-end to several 6502 cross-assemblers, including xasm