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Diffstat (limited to 'baremetal/500text-screen.mu')
| -rw-r--r-- | baremetal/500text-screen.mu | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/baremetal/500text-screen.mu b/baremetal/500text-screen.mu index 88ebc104..050cf4db 100644 --- a/baremetal/500text-screen.mu +++ b/baremetal/500text-screen.mu @@ -90,8 +90,17 @@ fn draw-grapheme screen: (addr screen), g: grapheme, x: int, y: int, color: int, copy-to *dest-color, src-color } +# not really needed for a real screen, though it shouldn't do any harm fn screen-cell-index screen-on-stack: (addr screen), x: int, y: int -> _/ecx: int { var screen/esi: (addr screen) <- copy screen-on-stack + # only one bounds check isn't automatically handled + { + var xmax/eax: (addr int) <- get screen, width + var xcurr/ecx: int <- copy x + compare xcurr, *xmax + break-if-< + abort "tried to print out of screen bounds" + } var height-addr/eax: (addr int) <- get screen, height var result/ecx: int <- copy y result <- multiply *height-addr |