RPROC

MON 60 subfunction RPROC = 077B (octal) = 0x3F = 63 decimal. NPL purpose (authoritative, 5P-P2-MON60.NPL): READ MESSAGE, server handler IRMESS.

Note: RPROC is the yaml client name for this subfunction; the authoritative server-side purpose is READ MESSAGE (IRMESS). Named here by the yaml client name RPROC; no operator command name is invented.

All addresses are OCTAL ND-100 word addresses, BANK 1, base 0. Source: SINTRAN/ND500/nd-500-mon/nd-500-mon-j04.prog.asm

Handler location - six call sites

Every site marshals two parameters: one word is a small constant loaded P-relative (a selector/code, role INFERRED) and one is a pointer to a buffer in the caller's frame; their slot order varies.

Call site	JPL	ptr -> thunk	Enclosing routine	,X 6	,X 7	Error (callsite+1)	Success (callsite+2)	Status
001332	JPL I 135	001467 -> 146613	001264 (fs 000153)	const (LDA 142)	&(B-170)	001333 JPL -42	001334 LDA ,B -152	PROVEN
001510	JPL I -21	001467 -> 146613	001264	const (LDA 37)	&(B-170)	001511 JPL I 136 -> 001271	001512 SAA 14	PROVEN
001545	JPL I -56	001467 -> 146613	001264	const (LDA -30)	&(B-170)	001546 JPL I 101 -> 001271	001547 LDA ,B -152	PROVEN
001625	JPL I -136	001467 -> 146613	001264	const (LDA -131)	&(B-170)	001626 JPL I 21 -> 001271	001627 LDA ,B -152	PROVEN
007531	JPL I 102	007633 -> 146613	002662 (fs 000331)	const (LDA 107)	&(B-52)	007532 JPL -32	007533 RADD ...	PROVEN
104456	JPL I 105	104563 -> 146613	103722 (fs 000605)	&(B-125)	const (LDA 106)	104457 JPL I -77 -> 103735	104460 JMP I 104 -> 105011	PROVEN

All six resolve to the single RPROC thunk 146613. The four sites in routine 001264 share pointer word 001467; their error paths converge on routine 001271.

Note on 001510: its parameters are stored at 001450-001455, then 001456 JMP 32 jumps over an intervening pointer/constant pool (001457-001507, mis-decoded as instructions per prog.md sec 9.1) to land exactly on the 001510 call. The call site is genuine; the store->call adjacency is broken only by that pool.

Thunk bytes (verified): 146613=170477 (SAA 77), 146614=125001, 146615=146244.

MON 60 subfunction used

Subfn	Octal / Hex / Dec	Thunk	Parameter-block layout	Skip/Error
RPROC	077B / 0x3F / 63	146613	2 words: a P-relative constant (selector) + a frame buffer pointer (order per site)	see per-site table

What it does

At each site the caller loads a small constant into one param slot and a pointer to a frame buffer into the other, then issues MON 60 RPROC to read a message. The four 001264 sites are variants (different constants) reading messages within one routine; 007531 is an interpreter case; 104456 reverses the slot order (buffer in slot 1).

Unknown / inferred

• PROVEN: two parameter words at every site.
• INFERRED: the P-relative constant is a message selector / mailbox id / length, and the frame pointer is the receive buffer. The exact constant values were not read back and the input/output split is not traced; the store operations are PROVEN.
• INFERRED (roles): routine 001264 is a message-reading routine (issues RPROC four times); 001271 is its local error target; 103722 a larger routine. ENTER addresses and framesizes are PROVEN; internal behaviour not carved.