[chbot] Programming 8-bit microcontrollers

[Mark Atherton]

would have defines 1000 as 1000L, so similar to synco, maybe cast 
setting to u32, the multiplied by 1000L

the layout of the class looks suspicious 3 x u8, 1 x u32, 1 x u8, 1 x 
u16 - would have tried to lay out on u32 boundaries : 1 x u32, 4 x u8, 1 
x u16

I can smell that Volker has set up some traps, so am looking for signed 
/ unsigned mixes, and extensions, but I see none ...

shouldn't this trap be awarded 'un poisson de chocolat'

-mark



On 23/09/2016 5:38 PM, Synco Reynders wrote:
 > To get a nice value for 'setting' you should cast to be 32 bit before 
multiplying. Like:
 > ms = (uint32_t) setting *1000
 >
 >
 > On 23 September 2016 at 15:34, Volker Kuhlmann 
<list0570 at paradise.net.nz> wrote:
 >
 >     This is for AVR, but should hold for any 8-bit job. Spot the 
problems:
 >
 >     static const uint16_t setting = 15*60;
 >     class values {
 >       uint8_t a, b, c;
 >       uint32_t d;
 >       uint8_t e;
 >       uint16_t f;
 >     };
 >     static const values defaults {
 >       50, 1, 10, 0xFFB070, 5, 0x03FF
 >     };
 >     void func() {
 >       unsigned long ms;
 >       ms = setting * 1000;
 >       ...
 >     }
 >
 >     The program doesn't work in 2 places.
 >
 >     First solution wins a free copy of the night light firmware.
 >
 >     First correct solution wins 2 free copies of the night light 
firmware.
 >
 >     Prize giving on Monday...
 >
 >     Volker
 >
 >     --
 >     Volker Kuhlmann
 >     http://volker.top.geek.nz/      Please do not CC list postings to me.
 >
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