mjb/altos/src, branch lisp

altos/draw: Add a reasonable API for drawing, add lines.

2016-11-21T05:02:59+00:00

Also, move the demo drawing into the stm-vga app and out of the vga driver. Signed-off-by: Keith Packard

altos: Don't wait while idle if trying to minimize interrupt latency

2016-11-21T04:56:01+00:00

Keeping the scanout running reasonably means keeping interrupt latency constant, and that requires leaving the CPU running. Don't wait for interrupts when the system is running in this mode. Signed-off-by: Keith Packard

altos/stm: Interrupt priority is in the upper bits of the priority mask

2016-11-21T04:54:10+00:00

Because the STM32L only offers 16 priority levels, the bottom four bits of each priority mask are not used. All of the interrupt priority settings in the system were using values < 16, making them all effectively the same. Fix that by moving them into the upper 4 bits and using symbolic constants everywhere. Signed-off-by: Keith Packard

altos/stm: Use basepri instead of primask for controlling interrupts

2016-11-21T04:48:40+00:00

This allows for high priority interrupts (priority 0) to run, even when other interrupts are blocked. Code executing in such interrupt handlers must not attempt to control task execution as that will race with the scheduler. Signed-off-by: Keith Packard

altos/stm-vga: Fix DMA reset to load scanline each time

2016-11-20T09:42:22+00:00

If we load the scanline register while DMA is running, it doesn't actually get reloaded until after the first transfer from the next line, leaving a weird jog in the middle of the screen. Also flip to SPI1, as Bdale is using that on the 1802 board. Signed-off-by: Keith Packard

altos/lisp: Clean up hanoi.lisp demo a bit

2016-11-20T09:41:59+00:00

No serious changes. Signed-off-by: Keith Packard

altos/stm-vga: Implement VGA out from the STM processor

2016-11-20T08:04:27+00:00

Generates vsync/hsync using timers and pixel data using the SPI port. 320x240 video using 640x480 mode and a 24MHz "pixel" clock. Includes the beginings of rendering code for the frame buffer, including bitblt, solid fill and text with a 5x7 font. Signed-off-by: Keith Packard

altos/lisp: Move stack recursion check after null check

2016-11-19T07:37:44+00:00

Don't crash when printing null stack this way. Signed-off-by: Keith Packard

altos/lisp: Include memory stats for test program

2016-11-19T06:57:22+00:00

Signed-off-by: Keith Packard

altos/lisp: Cleanup some DBG defines

2016-11-19T06:53:36+00:00

Get rid of the remaining duplicate defines. Signed-off-by: Keith Packard