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Diffstat (limited to 'docs/Bytecode')
| -rw-r--r-- | docs/Bytecode | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/docs/Bytecode b/docs/Bytecode new file mode 100644 index 0000000..4ed4135 --- /dev/null +++ b/docs/Bytecode @@ -0,0 +1,318 @@ +CSS style declaration bytecode +============================== + +Format +------ + +<opcode+flags> [<parameters>] + +<opcode+flags> is 32 bits wide. +The bottom 16 bits contain the opcode and the top 16 bits contain flags. + +The 16 bits of flag data are defined as follows: + bit 0 : !important + bit 1-15: MBZ + +Parameters are opcode-specific. Each parameter must begin on a 4 byte boundary. + +Datatype storage +---------------- + +8 and 16 bit integers are stored as 32bit values. + +32 and 64 bit integers are stored in their natural format. + +Floats and doubles are stored in their natural format. + +Strings are stored unterminated UTF8, preceded by 32bits of byte length, and +followed by 0-3 bytes of padding for alignment. The padding bytes must be +zero. The padding is not included in the byte length. + +CSS dimensions are stored as two 32bit values: <length, units>. +Length is a 32bit integer and unit is as follows: + + bit 8 clear => length unit + bits 9-31: MBZ + bits 0-7 : + 00000000 => px + 00000001 => ex + 00000010 => em + 00000011 => in + 00000100 => cm + 00000101 => mm + 00000110 => pt + 00000111 => pc + + bit 8 set => percentage unit + bits 9-31: MBZ + bits 0-7 : MBZ + + bit 9 set => angle unit + bits 10-31: MBZ + bit 8 : MBZ + bits 0-7 : + 00000000 => deg + 00000001 => grad + 00000010 => rad + + bit 10 set => time unit + bits 11-31: MBZ + bits 8-9 : MBZ + bits 0-7 : + 00000000 => ms + 00000001 => s + + bit 11 set => frequency unit + bits 12-31: MBZ + bits 8-10 : MBZ + bits 0-7 : + 00000000 => Hz + 00000001 => kHz + +CSS colours are stored as one 32bit value: + + bits 24-31: Red component + bits 16-23: Green component + bits 8-15 : Blue component + bits 0-7 : Alpha component + +CSS shapes are stored as one 32bit value followed by n CSS dimensions: + + bits 1-31: MBZ + bit 0 : clear => rect, 4 dimensions follow + set => reserved for future expansion + + TODO: how to handle "auto"? + + +Opcodes +------- + +00 - azimuth + <value> (32bits) : + bits 8-31: MBZ + bit 7 set => angle or inherit: + bits 0-6: 0000000 => signed angle unit follows, + 1111111 => inherit, + other => Reserved for future expansion. + bit 6 set => relative movement: + bit 7 : MBZ + bits 1-5: MBZ + bit 0 : set => rightwards, clear => leftwards + bits 6 & 7 clear => keyword position: + bit 5 : set => behind, clear => in front + bits 0-4: + 0000 => left-side + 0001 => far-left + 0010 => left + 0011 => center-left + 0100 => center + 0101 => center-right + 0110 => right + 0111 => far-right + 1000 => right-side + other => Reserved for future expansion. + +01 - background-attachment + <value> (32bits) : + 0 => fixed + 1 => scroll + 0xff => inherit + other => Reserved for future expansion. + +02 - background-color + <value> (32bits) : + bit 8-31: MBZ + bit 7 set => color or inherit: + bits 0-6: 0000000 => colour follows, + 1111111 => inherit, + other => Reserved for future expansion. + bit 7 clear => keyword color: + bits 1-6: MBZ + bit 0 : clear => transparent, set => rffe. + +03 - background-image + <value> (32bits) : + bits 8-31: MBZ + bit 7 set => uri or inherit: + bits 0-6: 0000000 => uri string follows, + 1111111 => inherit, + other => Reserved for future expansion. + bit 7 clear => keyword: + bits 1-6: MBZ + bit 0 : clear => none, set => rffe. + +04 - background-position + <value> (32bits) : + bits 8-31: MBZ + bits 0-7 : + 11111111 => inherit + otherwise: + bit 7: set => percentage or length unit follows + bits 4-6: MBZ + clear => keywords: + bits 4-6: + 000 => right + 001 => center + 010 => left + other => rffe + bit 3: set => percentage or length unit follows + bits 0-2: MBZ + clear => keywords: + bits 0-2: + 000 => bottom + 001 => center + 010 => top + other => rffe + +05 - background-repeat + <value> (32bits) : + 0 => no-repeat + 1 => repeat-x + 2 => repeat-y + 3 => repeat + 0xff => inherit + other => Reserved for future expansion. + +06 - border-collapse + <value> (32bits) : + 0 => separate + 1 => collapse + 0xff => inherit + other => Reserved for future expansion. + +07 - border-spacing + <value> (32bits) : + bits 8-31: MBZ + bits 0-7 : 00000000 => two lengths follow, + 11111111 => inherit, + other => Reserved for future expansion. + +08 - border-{top,right,bottom,left}-color + <value> (32bits) : + bits 10-31: MBZ + bits 8-9 : + 00 => top + 01 => right + 10 => bottom + 11 => left + bits 0-7 : 00000000 => colour follows, + 00000001 => transparent, + 11111111 => inherit, + other => Reserved for future expansion. + +09 - border-{top,right,bottom,left}-style + <value> (32bits) : + bits 10-31: MBZ + bits 8-9 : + 00 => top + 01 => right + 10 => bottom + 11 => left + bits 0-7 : + 00000000 => none, + 00000001 => hidden, + 00000010 => dotted, + 00000011 => dashed, + 00000100 => solid, + 00000101 => double, + 00000110 => groove, + 00000111 => ridge, + 00001000 => inset, + 00001001 => outset, + 11111111 => inherit, + other => Reserved for future expansion. + +0a - border-{top,right,bottom,left}-width + <value> (32bits) : + bits 10-31: MBZ + bits 8-9 : + 00 => top + 01 => right + 10 => bottom + 11 => left + bits 0-7 : + 11111111 => inherit, + otherwise: + bit 7 set => length follows + bits 0-6: MBZ + bit 7 clear => keywords: + bits 0-6: 0000000 => thin, + 0000001 => medium, + 0000010 => thick, + other => rffe. + +0b - bottom +0c - caption-side +0d - clear +0e - clip +0f - color +10 - content +11 - counter-increment +12 - counter-reset +13 - cue-after +14 - cue-before +15 - cursor +16 - direction +17 - display +18 - elevation +19 - empty-cells +1a - float +1b - font-family +1c - font-size +1d - font-style +1e - font-variant +1f - font-weight +20 - height +21 - left +22 - letter-spacing +23 - line-height +24 - list-style-image +25 - list-style-position +26 - list-style-type +27 - margin-{top,right,bottom,left} +28 - max-height +29 - max-width +2a - min-height +2b - min-width +2c - orphans +2d - outline-color +2e - outline-style +2f - outline-width +30 - overflow +31 - padding-{top,right,bottom,left} +32 - page-break-after +33 - page-break-before +34 - page-break-inside +35 - pause-after +36 - pause-before +37 - pitch-range +38 - pitch +39 - play-during +3a - position +3b - quotes +3c - richness +3d - speak-header +3e - speak-numeral +3f - speak-punctuation +40 - speak +41 - speech-rate +42 - stress +43 - table-layout +44 - text-align +45 - text-decoration +46 - text-indent +47 - text-transform +48 - top +49 - unicode-bidi +4a - vertical-align +4b - visibility +4c - voice-family +4d - volume +4e - white-space +4f - widows +50 - width +51 - word-spacing +52 - z-index +53-ffff - Reserved for future expansion. + |