Mercurial > repos > blastem
comparison runtime.S @ 149:139e5dcd6aa3
Make writes to control and data port block when DMA is in progress
| author | Mike Pavone <pavone@retrodev.com> |
|---|---|
| date | Tue, 01 Jan 2013 07:06:57 -0800 |
| parents | 15b8dce19cf4 |
| children | 3e68e517cc01 |
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| 148:4a400aec81bb | 149:139e5dcd6aa3 |
|---|---|
| 207 try_fifo_write: | 207 try_fifo_write: |
| 208 push %rdx | 208 push %rdx |
| 209 push %rbx | 209 push %rbx |
| 210 /* fetch VDP context pointer from 68K context */ | 210 /* fetch VDP context pointer from 68K context */ |
| 211 mov 128(%rsi), %rdx | 211 mov 128(%rsi), %rdx |
| 212 /* check DMA flag */ | |
| 213 bt $6, 19(%rdx) | |
| 214 jc fifo_fallback | |
| 212 /* get fifo_cur and compare it to fifo_end */ | 215 /* get fifo_cur and compare it to fifo_end */ |
| 213 mov (%rdx), %rbx | 216 mov (%rdx), %rbx |
| 214 cmp %rbx, 8(%rdx) | 217 cmp %rbx, 8(%rdx) |
| 215 /* bail out if fifo is full */ | 218 /* bail out if fifo is full */ |
| 216 je fifo_fallback | 219 je fifo_fallback |