mirror of https://github.com/uffejakobsen/acme.git
65 lines
2.6 KiB
Plaintext
65 lines
2.6 KiB
Plaintext
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ACME
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...the ACME Crossassembler for Multiple Environments
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--- floating-point support ---
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In release 0.92, ACME gained some experimental support for floating-
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point maths, so you can finally build sin/cos tables directly in ACME.
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But the expression parser still uses integer calculations per default.
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Here are the rules:
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a) if a maths operation is useless when done with integers, it is done
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with floats and returns a float. Applies to sin(), cos(), tan(),
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arcsin(), arccos(), arctan() and float(): These are always computed in
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float mode and always return floats.
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b) if a maths operation is useless when done with floats, it is done
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with integers and returns an integer. Applies to NOT, AND, OR, XOR,
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MOD, DIV, LSR, lowbyteof, highbyteof, bankbyteof and int(). These are
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always computed in integer mode and always return integers.
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c) All other mathematical operations are done in float mode if and
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only if at least one of the operands is a float. So "1/2*2" will give
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zero because it is done in integer mode, but "1.0/2*2" will give 1
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because it is done in float mode.
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To force a numerical value to be flagged as being a float, just add
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a decimal point and a zero. If a decimal value ends with a
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dot character, ACME switches to using the C type "double" and keeps
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reading digits. The value is then flagged internally as being float.
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CAUTION: Float usage is only activated when a decimal point has been
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found, so don't expect "100000000000000000000" to work.
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"100000000000000000000.0" won't work either, because when the decimal
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point gets parsed, the integer value will have overflown already. As
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there is no support yet for the "e" format (1e20 for 1*10^20) either,
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the only way to enter this value is by writing "1.0 * 10.0 ^ 20.0".
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Examples:
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!byte 1 / 2 * 2 ; gives 0 (integer maths)
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!byte 1 / 2 * 2.0 ; gives 0 (1/2 => 0 in integer maths,
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; float usage comes too late)
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!byte 1 / 2.0 * 2 ; gives 1 (FP in effect)
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!byte 1 / 2.0 * 2.0 ; gives 1 (FP in effect)
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!byte 1.0 / 2 * 2 ; gives 1 (FP in effect)
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!byte 1.0 / 2 * 2.0 ; gives 1 (FP in effect)
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!byte 1.0 / 2.0 * 2 ; gives 1 (FP in effect)
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!byte 1.0 / 2.0 * 2.0 ; gives 1 (FP in effect)
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You can use the new float() and int() functions to ensure the type of
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maths:
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!byte a / b * c ; depends on a/b/c's internal flags
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!byte float(a) / b * c ; calculation is done as float
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!byte int(a) / int(b) * int(c) ; calculation is done as int
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As you will have guessed, the trigonometric functions assume radians
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for measuring angles (90 degrees equals PI/2).
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Have a look at the example source code "trigono.a", it builds some
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sin/cos tables.
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