FreeCalypso > hg > freecalypso-tools
diff target-utils/compalstage/compalstage.S @ 11:21eec7569eb8
loadtools support for C139/140 target: -c 1004 compalstage variant
supercedes the previous -c 1003 version and supports the new C139 boot code
version found in the wild that expects "1004" or greater in the signature bytes
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Mon, 25 Jul 2016 21:09:33 +0000 |
| parents | e7502631a0f9 |
| children |
line wrap: on
line diff
--- a/target-utils/compalstage/compalstage.S Mon Jul 25 20:15:41 2016 +0000 +++ b/target-utils/compalstage/compalstage.S Mon Jul 25 21:09:33 2016 +0000 @@ -22,6 +22,25 @@ .word 0xFFFFFB10 #if PAD_TO_1003 +/* + * The older and most familiar versions of C139/140 boot code expect the + * signature bytes to be "1003" or greater, but a recently encountered + * newer version expects them to be "1004" or greater instead. As the + * actual comparison check in all currently known boot code versions is + * an inequality (the signature bytes in the downloaded image need to be + * greater than or equal to the hard-coded reference values), always + * putting "1004" in our compalstage image instead of "1003" should satisfy + * all existing C1xx boot code versions, or at least all currently known + * ones. However, having an image named compalstage-1003.bin with the + * corresponding -c 1003 loadtools option that is actually "1004" inside + * feels a little "wrong" in some sense, while getting rid of the -c 1003 + * option would break old user instructions, hence let's go ahead and do the + * silly exercise of building both "1003" and "1004" versions. + */ .org 0x3be0 +#if MAGIC_1004 + .ascii "1004" +#else .ascii "1003" #endif +#endif