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51 lines
1.3 KiB
Plaintext
51 lines
1.3 KiB
Plaintext
CP/M 3: Year 2000 fixes
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=======================
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The following archive contains all CP/M 3 .COM files that use dates,
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updated to operate correctly past the year 2000. They also allow dates to
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be in US or UK format.
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Operation: SETDEF
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=================
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To use UK-format dates, type:
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SETDEF [UK]
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To return to US-format dates, type:
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SETDEF [US]
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Operation: DATE
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===============
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The year entered when dates are set can be 0-77 (meaning 2000-2077) or 78-99
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(meaning 1978-1999). The problem of what to do in 2078 is deferred to a later
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revision of this program.
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Dates are now displayed with four-figure years.
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The US/UK setting applies to date entry and display.
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Operation: DIR and SHOW
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=======================
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DIR and SHOW display years above 2000 correctly (rather than as ":0") and
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obey the US/UK setting.
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Technical
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=========
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The US/UK setting is stored in a previously unused SCB byte. I have checked
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all available sources on the SCB (including the BDOS source) to come up with
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the following:
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SCB + 0Ch (xxA8h) bit 0: 0 for US, 1 for UK.
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This address is shown in the BDOS source as the low byte of an unused word
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in the "Utilities" section of the SCB. ZPM3 does not use this byte either.
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My recommendation is that any other expansions to utilities should use the
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remainder of this word to store settings.
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