100 lines
2.6 KiB
Forth
100 lines
2.6 KiB
Forth
fn main args: (addr array (addr array byte)) -> exit-status/ebx: int {
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var filename/eax: (addr array byte) <- first-arg args
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var file/esi: (addr buffered-file) <- load-file filename
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enable-screen-grid-mode
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var nrows/eax: int <- copy 0
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var ncols/ecx: int <- copy 0
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nrows, ncols <- screen-size 0
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enable-keyboard-immediate-mode
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{
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render file, nrows, ncols
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var key/eax: byte <- read-key
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compare key, 0x71 # 'q'
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loop-if-!=
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}
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enable-keyboard-type-mode
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enable-screen-type-mode
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exit-status <- copy 0
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}
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# decide how to lay out pages on screen
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fn render in: (addr buffered-file), nrows: int, ncols: int {
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# hardcoded parameter: page-width
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var toprow/eax: int <- copy 2
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var botrow/ecx: int <- copy toprow
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botrow <- add 0x20
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var leftcol/edx: int <- copy 5
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var rightcol/ebx: int <- copy leftcol
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rightcol <- add 0x30
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render-page in, toprow, leftcol, botrow, rightcol
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}
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fn render-page in: (addr buffered-file), toprow: int, leftcol: int, botrow: int, rightcol: int {
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clear toprow, leftcol, botrow, rightcol
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var row/ecx: int <- copy toprow
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$line-loop: {
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compare row, botrow
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break-if->=
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var col/edx: int <- copy leftcol
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move-cursor 0, row, col
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{
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compare col, rightcol
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break-if->=
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var c/eax: byte <- read-byte-buffered in
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compare c, 0xffffffff # EOF marker
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break-if-= $line-loop
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compare c, 0xa # newline
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break-if-= # no need to print newlines
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# print c
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print-byte 0, c
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col <- increment
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loop
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} # $char-loop
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row <- increment
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loop
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} # $line-loop
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}
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fn clear toprow: int, leftcol: int, botrow: int, rightcol: int {
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var row/ecx: int <- copy toprow
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{
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compare row, botrow
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break-if->=
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var col/edx: int <- copy leftcol
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move-cursor 0, row, col
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{
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compare col, rightcol
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break-if->=
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print-string 0, " "
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col <- increment
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loop
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}
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row <- increment
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loop
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}
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}
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fn first-arg args-on-stack: (addr array (addr array byte)) -> out/eax: (addr array byte) {
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var args/eax: (addr array (addr array byte)) <- copy args-on-stack
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var result/eax: (addr addr array byte) <- index args, 1
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out <- copy *result
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}
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fn load-file filename: (addr array byte) -> out/esi: (addr buffered-file) {
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var result: (handle buffered-file)
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{
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var tmp1/eax: (addr handle buffered-file) <- address result
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open filename, 0, tmp1
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}
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var tmp2/eax: (addr buffered-file) <- lookup result
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out <- copy tmp2
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}
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fn dump in: (addr buffered-file) {
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var c/eax: byte <- read-byte-buffered in
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compare c, 0xffffffff # EOF marker
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break-if-=
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print-byte 0, c
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loop
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}
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