alu_dec.h File Reference

GE-130 packed/signed decimal ALU helpers. More...

#include <stdint.h>
#include "ge.h"
#include "alu_cc.h"

Go to the source code of this file.

Functions
void	alu_ap (struct ge *ge, uint16_t a, uint8_t alen, uint16_t b, uint8_t blen)
	AP 0xEA Add Packed: op1 = op1 + op2; CC set.
void	alu_sp (struct ge *ge, uint16_t a, uint8_t alen, uint16_t b, uint8_t blen)
	SP 0xEB Subtract Packed: op1 = op1 - op2; CC set.
void	alu_mp (struct ge *ge, uint16_t a, uint8_t alen, uint16_t b, uint8_t blen)
	MP 0xEC Multiply Packed: op1 = op1 * op2; CC set.
void	alu_dp (struct ge *ge, uint16_t a, uint8_t alen, uint16_t b, uint8_t blen)
	DP 0xED Divide Packed: op1[left L1-L2 chars] = quotient, op1[right L2+1 chars] = remainder; CC set.
void	alu_cmp (struct ge *ge, uint16_t a, uint8_t alen, uint16_t b, uint8_t blen)
	CMP 0xE9 Compare Packed (algebraic, no operand change); CC set.
void	alu_mvp (struct ge *ge, uint16_t a, uint8_t alen, uint16_t b, uint8_t blen)
	MVP 0xE8 Move Packed: op1 = op2 (sign preserved from op2); CC set.
void	alu_pk (struct ge *ge, uint16_t dst, uint8_t dlen, uint16_t src, uint8_t slen)
	PK 0xDA Pack: zoned op2 → packed op1 (no sign processing).
void	alu_upk (struct ge *ge, uint16_t dst, uint8_t dlen, uint16_t src, uint8_t slen)
	UPK 0xD8 Unpack: packed op2 → zoned op1 (no sign processing; zone of each result byte is taken from the pre-existing zone in ge->mem).
void	alu_pks (struct ge *ge, uint16_t dst, uint8_t dlen, uint16_t src, uint8_t slen)
	PKS 0xEE Pack with Sign: zoned op2 → packed op1; sign from zone of rightmost source byte (zone 0xA → negative, else positive).
void	alu_upks (struct ge *ge, uint16_t dst, uint8_t dlen, uint16_t src, uint8_t slen)
	UPKS 0xEF Unpack with Sign: packed op2 → zoned op1; zone always 0x4.
void	alu_edt (struct ge *ge, uint16_t pattern, uint8_t plen, uint16_t src)
	EDT 0xDE Edit packed source into pattern at op1.
uint8_t	ge_ua_decimal (uint8_t bo, uint8_t ro, int subtract, int one_digit, uint8_t *carry)
	Arithmetic unit in decimal mode – one byte (two BCD digits), or one digit when CI50 restricts the unit to its low zone.

Detailed Description

GE-130 packed/signed decimal ALU helpers.

Operand model (manual §2.3.5 / §5.3, verified lines ~3148-3169): PACKED format: two BCD digits per byte; the rightmost (highest-address) byte holds one digit in the high nibble and the SIGN in the low nibble. Addresses supplied to every function are the address of the RIGHTMOST (least-significant, highest-address) byte of the operand — matching the manual's "address of the rightmost position" rule. Length parameter L → field is L+1 bytes long; digits = 2L+1 (always odd).

Sign codes (manual ~line 3155): 0xB (1011) and 0xD (1101) → negative all others → positive Generated sign: 0xC (positive), 0xD (negative)

ZONED format (for PK/UPK/PKS/UPKS, §5.5.3.4-5.5.3.5, §5.6.2): One digit per byte; low nibble = digit, high nibble = zone (normally 0xF for EBCDIC-style, but 0x4 in GE notation; PKS interprets zone 0xA in the LAST/rightmost character as negative sign). UPKS always generates zone 0x4 on all result characters.

Condition code (§5.6.1.x, all packed arithmetic / compare): FA04 FA05 (= cc bit1 cc bit0) 0 0 overflow (or, for CMP: L1 < L2 overflow) 0 1 result < 0 1 0 result = 0 1 1 result > 0

For PKS / UPKS: 0 0 not possible 0 1 result < 0 1 0 result = 0 1 1 result > 0

EDT / PK / UPK: CC not used.

Definition in file alu_dec.h.

Function Documentation

alu_ap()

void alu_ap	(	struct ge *	ge,
		uint16_t	a,
		uint8_t	alen,
		uint16_t	b,
		uint8_t	blen
	)

AP 0xEA Add Packed: op1 = op1 + op2; CC set.

Definition at line 255 of file alu_dec.c.

alu_cmp()

void alu_cmp	(	struct ge *	ge,
		uint16_t	a,
		uint8_t	alen,
		uint16_t	b,
		uint8_t	blen
	)

CMP 0xE9 Compare Packed (algebraic, no operand change); CC set.

Overflow if L1 < L2.

Definition at line 561 of file alu_dec.c.

alu_dp()

void alu_dp	(	struct ge *	ge,
		uint16_t	a,
		uint8_t	alen,
		uint16_t	b,
		uint8_t	blen
	)

DP 0xED Divide Packed: op1[left L1-L2 chars] = quotient, op1[right L2+1 chars] = remainder; CC set.

Overflow if: L1 <= L2, L2 > 7, divisor == 0, or result doesn't fit. On overflow, operation is NOT performed.

Definition at line 461 of file alu_dec.c.

alu_edt()

void alu_edt	(	struct ge *	ge,
		uint16_t	pattern,
		uint8_t	plen,
		uint16_t	src
	)

EDT 0xDE Edit packed source into pattern at op1.

pattern: address of leftmost byte of pattern; plen = pattern length (bytes). src: address of RIGHTMOST byte of packed source field. Pattern control chars: 0x20 = SST (digit substitute + zero suppress), 0x21 = TSZ (digit substitute, ends zero suppress), 0x22 = RSZ (reset zero suppress start), other = insertion char (kept as-is). First byte of pattern is the fill character. CC: 1 0 = zero suppression still active (result = 0); 1 1 = active off. (manual §5.5.3.6 / §5.5.3.7 CC table; note "not possible" for 0/1.)

Definition at line 870 of file alu_dec.c.

alu_mp()

void alu_mp	(	struct ge *	ge,
		uint16_t	a,
		uint8_t	alen,
		uint16_t	b,
		uint8_t	blen
	)

MP 0xEC Multiply Packed: op1 = op1 * op2; CC set.

Constraints: blen <= 8, blen < alen; op1 must have ≥blen+1 leading zero digits; otherwise overflow (CC=0, operation not performed).

Definition at line 360 of file alu_dec.c.

alu_mvp()

void alu_mvp	(	struct ge *	ge,
		uint16_t	a,
		uint8_t	alen,
		uint16_t	b,
		uint8_t	blen
	)

MVP 0xE8 Move Packed: op1 = op2 (sign preserved from op2); CC set.

Definition at line 616 of file alu_dec.c.

alu_pk()

void alu_pk	(	struct ge *	ge,
		uint16_t	dst,
		uint8_t	dlen,
		uint16_t	src,
		uint8_t	slen
	)

PK 0xDA Pack: zoned op2 → packed op1 (no sign processing).

Definition at line 684 of file alu_dec.c.

alu_pks()

void alu_pks	(	struct ge *	ge,
		uint16_t	dst,
		uint8_t	dlen,
		uint16_t	src,
		uint8_t	slen
	)

PKS 0xEE Pack with Sign: zoned op2 → packed op1; sign from zone of rightmost source byte (zone 0xA → negative, else positive).

CC set.

Definition at line 763 of file alu_dec.c.

alu_sp()

void alu_sp	(	struct ge *	ge,
		uint16_t	a,
		uint8_t	alen,
		uint16_t	b,
		uint8_t	blen
	)

SP 0xEB Subtract Packed: op1 = op1 - op2; CC set.

Definition at line 326 of file alu_dec.c.

alu_upk()

void alu_upk	(	struct ge *	ge,
		uint16_t	dst,
		uint8_t	dlen,
		uint16_t	src,
		uint8_t	slen
	)

UPK 0xD8 Unpack: packed op2 → zoned op1 (no sign processing; zone of each result byte is taken from the pre-existing zone in ge->mem).

Definition at line 730 of file alu_dec.c.

alu_upks()

void alu_upks	(	struct ge *	ge,
		uint16_t	dst,
		uint8_t	dlen,
		uint16_t	src,
		uint8_t	slen
	)

UPKS 0xEF Unpack with Sign: packed op2 → zoned op1; zone always 0x4.

CC set (reflects sign/value of packed source).

Definition at line 806 of file alu_dec.c.

ge_ua_decimal()

uint8_t ge_ua_decimal	(	uint8_t	bo,
		uint8_t	ro,
		int	subtract,
		int	one_digit,
		uint8_t *	carry
	)

Arithmetic unit in decimal mode – one byte (two BCD digits), or one digit when CI50 restricts the unit to its low zone.

carry is URPE in and out. See the comment on the definition for why subtract shares the binary line.

Definition at line 939 of file alu_dec.c.