sd:sd-8516_stellar_basic
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| sd:sd-8516_stellar_basic [2026/04/24 13:52] – appledog | sd:sd-8516_stellar_basic [2026/04/28 15:55] (current) – appledog | ||
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| == It's fast! | == It's fast! | ||
| - | Stellar BASIC is a kind of 8 bit TinyBASIC, with a few improvements under the hood. It can execute over 3,000 lines per second at 4 MHz (1.28 MIPS)! Although of course, graphics-heavy statements can slow this down to 800 lines/ | + | Stellar BASIC is a kind of 8 bit TinyBASIC, with a few improvements under the hood. It can execute over 3,000 lines per second at 4 MHz! Although of course, graphics-heavy statements can slow this down to about half that. Check out our [[Practical Speed Tests]]. |
| Now, compared to a C64 running at 1mhz, why is it so fast? You would expect it to top out at ~800 lines per second since it's four times faster. First, the SD-8516 does not experience the register pressure of a 6502. With more registers available to the programmer, the code size is smaller, and therefore faster. | Now, compared to a C64 running at 1mhz, why is it so fast? You would expect it to top out at ~800 lines per second since it's four times faster. First, the SD-8516 does not experience the register pressure of a 6502. With more registers available to the programmer, the code size is smaller, and therefore faster. | ||
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| </ | </ | ||
| - | The problem with this is that it's a bit slow. In fact, it executes in 6 seconds at 100mhz. | + | The problem with this is that it's a bit slow. In fact, it takes over a minute to finish drawing! |
| - | The reason why it takes so long is because Mode 3 uses a packed pixel format -- one byte holds two pixels (each pixel is four bits). In fact, if we wrote this program normally it would take over 12 seconds | + | The reason why it takes so long is because Mode 3 uses a packed pixel format -- one byte holds two pixels (each pixel is four bits). In fact, if we wrote this program normally it would take even longer to finish, |
| - | If you'd like to use something a bit faster, you can try the 2d accelerated graphics commands PIXEL and PEXEL. | + | Let's try something a bit faster; the 2d accelerated graphics commands PIXEL and PEXEL. |
| === PIXEL and PEXEL | === PIXEL and PEXEL | ||
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| 30 FOR X = 0 TO 19 | 30 FOR X = 0 TO 19 | ||
| 40 FOR Y = 0 TO 199 | 40 FOR Y = 0 TO 199 | ||
| - | 50 PIXEL(C * 20 + X, Y, C) | + | 50 PIXEL C * 20 + X, Y, C |
| 60 NEXT Y | 60 NEXT Y | ||
| 70 NEXT X | 70 NEXT X | ||
| Line 113: | Line 113: | ||
| 90 REM DIAGONAL LINE IN WHITE | 90 REM DIAGONAL LINE IN WHITE | ||
| 100 FOR I = 0 TO 199 | 100 FOR I = 0 TO 199 | ||
| - | 110 PIXEL(I, I, 3) | + | 110 PIXEL I, I, 3 |
| 120 NEXT I | 120 NEXT I | ||
| 130 INPUT "PRESS ENTER"; | 130 INPUT "PRESS ENTER"; | ||
| Line 119: | Line 119: | ||
| </ | </ | ||
| - | If you time this program you will find that it is even slower | + | If you time this program you will find that it is vastly faster |
| === 160x200 CGA Mode | === 160x200 CGA Mode | ||
| Line 139: | Line 139: | ||
| It's still slow to POKE, but if you're just drawing a scene or some letters or art, you can easily get away with POKE in 160x200 mode. | It's still slow to POKE, but if you're just drawing a scene or some letters or art, you can easily get away with POKE in 160x200 mode. | ||
| - | |||
| === LINE | === LINE | ||
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| </ | </ | ||
| - | Line drawing is much faster. It takes 0.14 seconds at 100mhz. That is an incredible speed-up over the previous record. But there is an even faster command than this -- the RECT drawing command. | + | Line drawing is much faster. It takes under a second. That is an incredible speed-up over the previous record. But there is an even faster command than this, the RECT drawing command. |
| === RECT | === RECT | ||
| - | Yes! What's even better than a LINE? A rectangle! | + | What's even better than a LINE? A rectangle, of course. |
| <codify BASIC> | <codify BASIC> | ||
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| </ | </ | ||
| - | This program is even shorter than the others, and ever so much faster! Clocking in at well under a tenth of a second, | + | This program is even shorter than the others, and ever so much faster. It's so fast you may have trouble timing |
| === CIRCLE | === CIRCLE | ||
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| 60 MODE 1 | 60 MODE 1 | ||
| </ | </ | ||
| + | |||
| + | The format is: | ||
| + | |||
| + | CIRCLE x1,y1, xr, yr, color | ||
| Now you can create truly stunning art on the SD-8516! | Now you can create truly stunning art on the SD-8516! | ||
sd/sd-8516_stellar_basic.1777038758.txt.gz · Last modified: by appledog