collapseos/blk/398

: IF ( -- a | a: br cell addr )
    0x67 ( ?br ) , H@ 2 ALLOT ( br cell allot )
; IMMEDIATE
: THEN ( a -- | a: br cell addr )
    DUP H@ -^ _bchk SWAP ( a-H a ) !
; IMMEDIATE
: ELSE ( a1 -- a2 | a1: IF cell a2: ELSE cell )
    0x53 ( br ) ,
    2 ALLOT
    [COMPILE] THEN
    H@ 2- ( push a. -2 for allot offset )
; IMMEDIATE
Limit ourselves to 8-bit branching I'm planning on going back to 8-bit branching. 16-bit br cells incur a non-negligible penalty and, while at first 64 words (128 bytes forward or backward) seemed a bit limiting, I now don't see why one would ever construct such a big branch. It would be un-forthy. Also, I looked at using BC instead of IY to hold IP and the transition would be a lot easier with 8-bit branching. In this commit, all I do is add overflow checks in IF. The mechanic below doesn't change. I'll give myself some time to think it over so that I avoid yet another back and forth. 2020-05-25 00:01:46 +10:00			`: IF ( -- a \| a: br cell addr )`
Refer to stable wordref by direct offset in "hot zone" immediates Previously, it was impossible to cross-compile Collapse OS from a binary-offsetted Collapse OS because stable ABI wordrefs would have a wrongly offsetted address. This solves the problem by replacing those wordrefs by direct, hardcoded stable ABI offset references. 2020-07-05 21:09:11 +10:00			`0x67 ( ?br ) , H@ 2 ALLOT ( br cell allot )`
Move Cross-compiled core from B390 to B350 and renamed it "Core words". Also, reworded the presentation. 2020-05-16 12:44:49 +10:00			`; IMMEDIATE`
Limit ourselves to 8-bit branching I'm planning on going back to 8-bit branching. 16-bit br cells incur a non-negligible penalty and, while at first 64 words (128 bytes forward or backward) seemed a bit limiting, I now don't see why one would ever construct such a big branch. It would be un-forthy. Also, I looked at using BC instead of IY to hold IP and the transition would be a lot easier with 8-bit branching. In this commit, all I do is add overflow checks in IF. The mechanic below doesn't change. I'll give myself some time to think it over so that I avoid yet another back and forth. 2020-05-25 00:01:46 +10:00			`: THEN ( a -- \| a: br cell addr )`
			`DUP H@ -^ _bchk SWAP ( a-H a ) !`
Move Cross-compiled core from B390 to B350 and renamed it "Core words". Also, reworded the presentation. 2020-05-16 12:44:49 +10:00			`; IMMEDIATE`
Limit ourselves to 8-bit branching I'm planning on going back to 8-bit branching. 16-bit br cells incur a non-negligible penalty and, while at first 64 words (128 bytes forward or backward) seemed a bit limiting, I now don't see why one would ever construct such a big branch. It would be un-forthy. Also, I looked at using BC instead of IY to hold IP and the transition would be a lot easier with 8-bit branching. In this commit, all I do is add overflow checks in IF. The mechanic below doesn't change. I'll give myself some time to think it over so that I avoid yet another back and forth. 2020-05-25 00:01:46 +10:00			`: ELSE ( a1 -- a2 \| a1: IF cell a2: ELSE cell )`
Refer to stable wordref by direct offset in "hot zone" immediates Previously, it was impossible to cross-compile Collapse OS from a binary-offsetted Collapse OS because stable ABI wordrefs would have a wrongly offsetted address. This solves the problem by replacing those wordrefs by direct, hardcoded stable ABI offset references. 2020-07-05 21:09:11 +10:00			`0x53 ( br ) ,`
Move Cross-compiled core from B390 to B350 and renamed it "Core words". Also, reworded the presentation. 2020-05-16 12:44:49 +10:00			`2 ALLOT`
Limit ourselves to 8-bit branching I'm planning on going back to 8-bit branching. 16-bit br cells incur a non-negligible penalty and, while at first 64 words (128 bytes forward or backward) seemed a bit limiting, I now don't see why one would ever construct such a big branch. It would be un-forthy. Also, I looked at using BC instead of IY to hold IP and the transition would be a lot easier with 8-bit branching. In this commit, all I do is add overflow checks in IF. The mechanic below doesn't change. I'll give myself some time to think it over so that I avoid yet another back and forth. 2020-05-25 00:01:46 +10:00			`[COMPILE] THEN`
			`H@ 2- ( push a. -2 for allot offset )`
Move Cross-compiled core from B390 to B350 and renamed it "Core words". Also, reworded the presentation. 2020-05-16 12:44:49 +10:00			`; IMMEDIATE`