retitle 423910 z80asm: Should warn when truncating values to 8 bit severity 423910 wishlist tags 423910 upstream thanks
Hi, Thanks for reporting this issue. However, I do not agree it is a bug. "ld b, (0xbeef)" is an instruction of the form "ld b, expression". In this case the expression is in parenthesis, which is strange, but not invalid. For example, "ld b, 2 * (1 + 4)" is also allowed. In that case only part of the expression is in parenthesis, so it looks less strange (and confusing). "ld b, (0xbeef)" is equal to "ld b, 0xbeef", but since b is an 8-bit register, the upper bits are truncated. That leaves "ld b, 0xbeef & 0xff", which is "ld b, 0xef". I agree that a warning is appropriate when this truncation takes place. Therefore I am changing this bug into a feature request for that. In most cases, that will lead to an unexpected warning when trying to assemble "ld b, (0xbeef)", which should make debugging such a problem much easier. Thanks, Bas Wijnen On Tue, May 15, 2007 at 12:21:18AM +0200, Tomaz Solc wrote: > z80asm does not report an error when an input file contains invalid > Z80 instructions. > > Example source file that demonstrates this bug: > > ld a,(0xbeef) ; valid > ld b,(0xbeef) ; invalid (no such instruction exists on Z80) > > z80asm will produce the following machine code (hex dump): > > 3a ef be 06 ef > > "3a ef be" is the correct code for "ld a,(0xbeef)". > > "06 ef" is code for "ld b,0xef". > > The correct behavior would be to print an error message instead of producing > code that does not match the source file. -- I encourage people to send encrypted e-mail (see http://www.gnupg.org). If you have problems reading my e-mail, use a better reader. Please send the central message of e-mails as plain text in the message body, not as HTML and definitely not as MS Word. Please do not use the MS Word format for attachments either. For more information, see http://pcbcn10.phys.rug.nl/e-mail.html
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