90-Day Execution Timelines and Attainable Milestones

Metadata

Field	Value
source	../Assembly-Versus-Fortran-Comparison.md
document	Comparative Strategic Analysis of Assembly and Fortran for 1980s–1990s Constrained Game Development: Low-Level Optimization, Simulation Architecture, and Modern Player Experience
kind	section-lead
parent
lines	24-34
findings	D02-C4 D02-C5 D02-M4 D02-m4

The three-month acquisition trajectory differs markedly depending on whether the developer chooses Assembly (such as 16-bit x86 DOS or MOS 6502/68000) or Fortran (such as FORTRAN 77 under DOS or Modern Fortran compiled with retro toolchains)1.

Week Interval	Assembly Pathway (x86 Real Mode / DOS Mode 13h)	Fortran Pathway (FORTRAN 77 / Modern Fortran)
Weeks 1–4	CPU registers, binary logic, stack management; setting up BIOS interrupts (INT 10h for Mode 13h); plotting pixels directly to 0xA000:00008.	Variable typing; DO loop logic; multidimensional arrays; array indexing; basic ASCII graphics and game state structures6.
Weeks 5–8	Fast memory copy (REP MOVSW/MOVSD); fixed-point trigonometry math; double-buffering in conventional RAM; keyboard IRQ (INT 09h) handling1.	Matrix transformations; celestial mechanics; cellular automata loops; procedural map generation; file save/load routines3.
Weeks 9–12	Tile blitting routines; vertical blank synchronization (V-Sync on port 0x3DA); custom fixed-point raycasting or 2D sprite engine1.	Complex deterministic economy/simulation engine; integration with low-level drawing wrappers or ANSI text terminal rendering12.
Attainable Milestone	A fully functional, smooth 60/70 FPS 2D action game, tile scroller, or pseudo-3D raycaster written bare-metal1.	A deep, complex simulation game (e.g., hard-sci-fi flight dynamics, tactical wargame, or procedural roguelike)11.

Review findings for this part

The findings come from ../../findings/ (pass 1). The script matches them to this part by source line.

ID	Severity	Evidence	Status	Location	Problem
D02-C4	critical	KNOW DOC	open	L33, L42, L112, L166	Claim: The document promises “Locked 60/70 FPS” and V-Sync “completely eliminating tearing” in Mode 13h.. Problem: (a) Mode 13h runs at 70 Hz. Thus a game locked to vsync gets 70 or 35 fps, not a locked 60. (b) Mode 13h has one page, thus page flipping is not possible. A copy of 64,000 bytes in the ~1 to 1.5 ms vertical blank is not possible over ISA. As a result, tearing becomes less, but it does not stop. Flipping without tears needs Mode X (L11 mentions it, but the roadmap does not use it). (c) The figure in the document (L70), 3.84 MB/s, is more than many 8/16-bit ISA VGA cards can supply.
D02-C5	critical	KNOW	open	L33	Claim: The 90-day milestone is a “fully functional, smooth 60/70 FPS … raycaster written bare-metal”.. Problem: This is not realistic for a person who learns assembly from zero. Commercial teams with C plus assembly shipped raycasters that ran much slower than 60 fps on the hardware of that time. No evidence supports the timeline.
D02-M4	major	KNOW	open	L41, L30–31	Claim: The document does 16.16 fixed point “using AX, BX, CX, DX”.. Problem: These are 16-bit registers. 16.16 math needs 32-bit registers (EAX and the others, 386 and later) or register pairs on the 8086. `REP MOVSD` (L31) also needs a 386 or later. The document mixes 8086 and 386 targets and does not say so.
D02-m4	minor	VERIFY	verify	L26	The document says “Modern Fortran compiled with retro toolchains”. But it names no DOS toolchain that supports modern Fortran. A DJGPP gfortran port can possibly exist, but the document does not mention one.

Review worksheet

1. Goal of this part

What does this part try to show, or help the reader decide?

2. Key claims to test

#	Claim	Evidence given (citation / data)	Verifiable?
1

3. Adversarial review

Strongest counter-argument:
Unsupported, overstated, or outdated claims:
Source quality (primary vs. blog/forum/marketing):
Omissions / what a skeptic would ask:
Internal consistency with other segments:

4. Evaluation

Does the segment achieve its goal? (Yes / Partly / No)
Confidence: (High / Medium / Low)
Required fixes: