6469

Let's start committing new prototype directories *before* we start hacking
on them. Version control is useful right from the draft when programming
in a language without any error messages.

1 files changed, 128 insertions, 0 deletions

diff --git a/prototypes/browse/20/screen-position-state.mu b/prototypes/browse/20/screen-position-state.mu
new file mode 100644
index 00000000..3bfd361b
--- /dev/null
+++ b/prototypes/browse/20/screen-position-state.mu
@@ -0,0 +1,128 @@
+type screen-position-state {
+  nrows: int  # const
+  ncols: int  # const
+  toprow: int
+  botrow: int
+  leftcol: int
+  rightcol: int
+  row: int
+  col: int
+}
+
+fn init-screen-position-state _self: (addr screen-position-state) {
+  # hardcoded parameters:
+  #   top-margin
+  #   page-margin
+  #   text-width
+  #   page-height (temporary)
+  var self/esi: (addr screen-position-state) <- copy _self
+  var nrows/eax: int <- copy 0
+  var ncols/ecx: int <- copy 0
+  nrows, ncols <- screen-size
+  var dest/edx: (addr int) <- copy 0
+  # self->nrows = nrows
+  dest <- get self, nrows
+  copy-to *dest, nrows
+  # self->ncols = ncols
+  dest <- get self, ncols
+  copy-to *dest, ncols
+  # self->toprow = top-margin
+  dest <- get self, toprow
+  copy-to *dest, 2  # top-margin
+  # self->botrow = nrows
+  dest <- get self, botrow
+  copy-to *dest, 0x22  # top-margin + page-height
+  # self->leftcol = page-margin
+  dest <- get self, leftcol
+  copy-to *dest, 5  # left-margin
+  # self->rightcol = self->leftcol + text-width
+  dest <- get self, rightcol
+  copy-to *dest, 0x45  # left-margin + text-width
+  #
+  start-drawing self
+}
+
+fn start-drawing _self: (addr screen-position-state) {
+  var self/esi: (addr screen-position-state) <- copy _self
+  var tmp/eax: (addr int) <- copy 0
+  var tmp2/ecx: int <- copy 0
+  # self->row = self->toprow
+  tmp <- get self, toprow
+  tmp2 <- copy *tmp
+  tmp <- get self, row
+  copy-to *tmp, tmp2
+  # self->col = self->leftcol
+  tmp <- get self, leftcol
+  tmp2 <- copy *tmp
+  tmp <- get self, col
+  copy-to *tmp, tmp2
+  #
+  reposition-cursor self
+}
+
+fn add-char _self: (addr screen-position-state), c: byte {
+  var self/esi: (addr screen-position-state) <- copy _self
+  # print c
+  print-byte c
+  # self->col++
+  var tmp/eax: (addr int) <- get self, col
+  increment *tmp
+  # if (self->col > self->rightcol) next-line(self)
+  var tmp2/ecx: int <- copy *tmp
+  tmp <- get self, rightcol
+  compare tmp2, *tmp
+  {
+    break-if-<=
+    next-line self
+    reposition-cursor self
+  }
+}
+
+fn next-line _self: (addr screen-position-state) {
+  var self/esi: (addr screen-position-state) <- copy _self
+  # self->row++
+  var tmp/eax: (addr int) <- get self, row
+  increment *tmp
+  # if (self->row > self->botrow) next-page(self)
+  var tmp2/ecx: int <- copy *tmp
+  tmp <- get self, botrow
+  compare tmp2, *tmp
+  {
+    break-if-<=
+    next-page self
+  }
+}
+
+fn next-page _self: (addr screen-position-state) {
+  var self/esi: (addr screen-position-state) <- copy _self
+  # TMP
+  var tmp/eax: (addr int) <- get self, row
+  increment *tmp
+}
+
+fn done-drawing? _self: (addr screen-position-state) -> result/eax: boolean {
+  var self/esi: (addr screen-position-state) <- copy _self
+  # TMP
+  var r/eax: (addr int) <- get self, row
+  var tmp/ecx: (addr int) <- get self, botrow
+  var max/ecx: int <- copy *tmp
+$done-drawing?:check: {
+    compare *r, max
+    {
+      break-if->=
+      result <- copy 0  # false
+      break $done-drawing?:check
+    }
+    {
+      break-if-<
+      result <- copy 1  # true
+    }
+  }
+}
+
+fn reposition-cursor _self: (addr screen-position-state) {
+  var self/esi: (addr screen-position-state) <- copy _self
+  var r/eax: (addr int) <- get self, row
+  var c/ecx: (addr int) <- get self, col
+  move-cursor *r *c
+}