* Re: [Qemu-devel] [PATCH v5 6/8] target/mips: Define the R5900 CPU [not found] ` <alpine.LFD.2.21.1809210020490.19067@eddie.linux-mips.org> @ 2018-10-21 12:34 ` Fredrik Noring 2018-10-21 15:21 ` Maciej W. Rozycki 0 siblings, 1 reply; 2+ messages in thread From: Fredrik Noring @ 2018-10-21 12:34 UTC (permalink / raw) To: Maciej W. Rozycki Cc: Philippe Mathieu-Daudé, Richard Henderson, Aleksandar Markovic, Aurelien Jarno, Petar Jovanovic, Peter Maydell, Jürgen Urban, qemu-devel Hi Maciej, > The C790 is a follow-up to the R5900. The R5900 has an FPU that is not > compliant to the IEEE 754 standard for floating-point arithmetic. It > doesn't implement exceptions, infinities, NaNs or denormals. It doesn't > implement the the double format either, but that is really tangential, > because the same was the case with the IDT R4650, which had a standard > IEEE 754 FPU, but no double format either. Finally it has some anomalies > in the FP instruction set; not all opcode encodings are standard. Do you know where one might find a list of the nonstandard FP instructions? The command % grep 'FP_.*EE' binutils/opcodes/mips-opc.c gives a list of candidates, I suppose? Fredrik ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH v5 6/8] target/mips: Define the R5900 CPU 2018-10-21 12:34 ` [Qemu-devel] [PATCH v5 6/8] target/mips: Define the R5900 CPU Fredrik Noring @ 2018-10-21 15:21 ` Maciej W. Rozycki 0 siblings, 0 replies; 2+ messages in thread From: Maciej W. Rozycki @ 2018-10-21 15:21 UTC (permalink / raw) To: Fredrik Noring Cc: Philippe Mathieu-Daudé, Richard Henderson, Aleksandar Markovic, Aurelien Jarno, Petar Jovanovic, Peter Maydell, Jürgen Urban, qemu-devel Hi Fredrik, > > The C790 is a follow-up to the R5900. The R5900 has an FPU that is not > > compliant to the IEEE 754 standard for floating-point arithmetic. It > > doesn't implement exceptions, infinities, NaNs or denormals. It doesn't > > implement the the double format either, but that is really tangential, > > because the same was the case with the IDT R4650, which had a standard > > IEEE 754 FPU, but no double format either. Finally it has some anomalies > > in the FP instruction set; not all opcode encodings are standard. > > Do you know where one might find a list of the nonstandard FP instructions? > > The command > > % grep 'FP_.*EE' binutils/opcodes/mips-opc.c > > gives a list of candidates, I suppose? Yeah, those that have EE in `membership' are extra and those that have EE in `exclusions' are missing. See also: <https://sourceware.org/ml/binutils/2012-11/msg00360.html>. Maciej ^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-10-21 12:34 ` [Qemu-devel] [PATCH v5 6/8] target/mips: Define the R5900 CPU Fredrik Noring
2018-10-21 15:21 ` Maciej W. Rozycki
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