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Fix QINT doc #278

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Merged
mooinglemur merged 6 commits into from
Nov 21, 2025
Merged

Fix QINT doc #278

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5a8266e
fix: document difference in X16 FOUT behavior
markjreed Jul 7, 2025
8d43ea8
fix: correct typos
markjreed Jul 7, 2025
a213a72
fix: result of QINT is signed (i32), not unsigned (u32)
markjreed Nov 19, 2025
c9b29ba
fix: QINT is there on c64, not an X16 addition
markjreed Nov 19, 2025
c2587c6
fix: change format of description to match rest of format conversions…
markjreed Nov 19, 2025
956c441
fix: spell FACC correctly
markjreed Nov 19, 2025
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10 changes: 8 additions & 2 deletions X16 Reference - 06 - Math Library.md
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Original file line number Diff line number Diff line change
Expand Up @@ -13,10 +13,17 @@ The following functions are available from machine language code after setting t
|---------|----------|----------------------------------------------------------------------------------------------|
| $FE00 | `AYINT` | convert floating point to integer (signed word) |
| $FE03 | `GIVAYF` | convert integer (signed word) to floating point |
| $FE06 | `FOUT` | convert floating point to ASCII string |
| $FE06 | `FOUT` | convert floating point to ASCII string. (See below) |
| $FE09 | `VAL_1` | convert ASCII string in .X:.Y length in .A, to floating point in FACC. _Caveat! Read below!_ |
| $FE0C | `GETADR` | convert floating point to an address (unsigned word) |
| $FE0F | `FLOATC` | convert address (unsigned word) to floating point |
| $FE8D | `QINT` | convert floating point to signed 32-bit integer (which is stored in the FACC mantissa bytes in big-endian order) |

**Difference in X16 Behavior of FOUT**

The version of FOUT described in the book leaves a pointer to the result string
in the AY register pair; the X16 version does not do that. Instead, rely on the
string always being placed in the FBUFFR location at $0100.

**Important caveat ragarding the `VAL_1` routine in its current implementation:**

Expand All @@ -33,7 +40,6 @@ The following calls are new to the X16 and were not part of the C128 math librar
|---------|----------|-------------------------------------------------|
| $FE87 | `FLOAT` | FACC = (s8).A convert signed byte to float |
| $FE8A | `FLOATS` | FACC = (s16)facho+1:facho |
| $FE8D | `QINT` | facho:facho+1:facho+2:facho+3 = u32(FACC) |
| $FE93 | `FOUTC` | Convert FACC to ASCIIZ string at fbuffr - 1 + .Y |

## Movement
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