COMMON/common/common.h
2018-08-07 06:38:40 -04:00

143 lines
4.5 KiB
C

#ifndef __COMMON_H
#define __COMMON_H
; Using four byte quantities aabbccdd with sign bit, overflow/underflow bit, 20 bits significand, 10 bits
; fraction. The quantity is valid if the overflow/underflow bit agrees with the sign bit. The intent is
; to be able to recognize an overflow/underflow situation, rescale the arguments, and repeat the
; calculation.
; Largest value: $3fffffff or 1048575.999(9)
; Smallest value: $c0000001 or -1048575.999(0)
; Largest value for DEC: $3d08ffff or 999999.999(9)
; Smallest value for DEC: $c2f70001 or -999999.999(0)
; Instructions
; SET r aabbcc.dd 1r dd cc bb aa Rr <- aabbccdd - set register
; POP r 2r Rr <- RS - pop from stack
; PSH r 3r RS <- Rr - push onto stack
; EXC r 4r Rr <-> RS - exchange Rr with stack
; INR r 5r Rr <- Rr + 1.0 - increment register
; DCR r 6r Rr <- Rr - 1.0 - decrement register
; TST r 7r F <- Rr <=> 0.0 - test register
; DEC r 8r Rr <- dec(Rr) - convert Rr from hex aabbccdd to decimal #########
; HEX r 9r Rr <- hex(Rr) - convert Rr from decimal ######### to hex aabbccdd
; ADD r pq ar pq Rr <- Rp + Rq - addition
; SUB r pq br pq Rr <- Rp - Rq - subtraction
; MUL r pq cr pq Rr <- Rp * Rq - multiplication
; DIV r pq dr pq Rr <- Rp / Rq - division
; MOD r pq er pq Rr <- Rp % Rq - modulus
; EXT z ... fz ... - system and user defined functions
; ESC 00 - escape back into regular assembler
; RTN 01 - return from subroutine
; BRS xxyy 02 yy xx PC <- PC + xxyy - branch to subroutine
; BRA xxyy 03 yy xx PC <- PC + xxyy - branch always
; BRE xxyy 04 yy xx PC <- PC + xxyy - branch if Rp = Rq (after CMR)
; BRG xxyy 05 yy xx PC <- PC + xxyy - branch if Rp > Rq (after CMR)
; BRL xxyy 06 yy xx PC <- PC + xxyy - branch if Rp < Rq (after CMR)
; BRZ xxyy 07 yy xx PC <- PC + xxyy - branch if Rr = 0.0 (after TST)
; BRP xxyy 08 yy xx PC <- PC + xxyy - branch if Rr > 0.0 (after TST)
; BRN xxyy 09 yy xx PC <- PC + xxyy - branch if Rr < 0.0 (after TST)
; BRO xxyy 0a yy xx PC <- PC + xxyy - branch if overflow (after arithmetic operations)
; BRU xxyy 0b yy xx PC <- PC + xxyy - branch if underflow (after arithmetic operations)
; CPR pq 0c pq Rp <- Rq - copy register
; LDI pq 0d pq Rp <- (int(Rq)) - load indirect from memory
; SVI pq 0e pq (int(Rp)) <- Rq - save indirect to memory
; CMR pq 0f pq F <- Rp <=> Rq - compare registers
; 64 bytes in page zero for common registers
_R0 = $C0
_R1 = _R0 + 4
_R2 = _R1 + 4
_R3 = _R2 + 4
_R4 = _R3 + 4
_R5 = _R4 + 4
_R6 = _R5 + 4
_R7 = _R6 + 4
_R8 = _R7 + 4
_R9 = _R8 + 4
_RA = _R9 + 4
_RB = _RA + 4
_RC = _RB + 4 ; workspace for arithmetic operations
_RD = _RC + 4 ; as above and for EXC
_RE = _RD + 4 ; register E maintains common status
_RF = _RE + 4 ; register F saves/restores processor status
; register E maintains common status
; (dd cc bb aa) aa: index for register stack RS / ccbb: program counter PC / dd: flags F UONPZLGE
_RSI = _RE ; register stack index
_PCL = _RSI + 1 ; program counter low
_PCH = _PCL + 1 ; program counter high
_F = _PCH + 1 ; flags
_PC = _PCL ; program counter
; bits for flags
_F_E = 1 ; if Rp = Rq (after CMP)
_F_G = 2 ; if Rp > Rq (after CMP)
_F_L = 4 ; if Rp < Rq (after CMP)
_F_Z = 8 ; if Rr = 0.0 (after TST)
_F_P = 16 ; if Rr > 0.0 (after TST)
_F_N = 32 ; if Rr < 0.0 (after TST)
_F_O = 64 ; if overflow (after arithmetic operations)
_F_U = 128 ; if underflow (after arithmetic operations)
; register F saves/restores processor status
; (dd cc bb aa) aa: accumulator, bb: index X, cc: index Y, dd: processor status
_ACC = _RF ; saved accumulator to restore
_IDX = _ACC + 1 ; saved index X to restore
_IDY = _IDX + 1 ; saved index Y to restore
_PS = _IDY + 1 ; saved processor status to restore
; 256 bytes of page two
_RS = $200 ; register stack
; 64 bytes of page three
FN_FX = $300 ; list of system and user functions
; function constants
_ESC_C = $00
_RTN_C = $01
_BRS_C = $02
_BRA_C = $03
_BRE_C = $04
_BRG_C = $05
_BRL_C = $06
_BRZ_C = $07
_BRP_C = $08
_BRN_C = $09
_BRO_C = $0a
_BRU_C = $0b
_CPR_C = $0c
_LDI_C = $0d
_SVI_C = $0e
_CMR_C = $0f
_SET_C = $10
_POP_C = $20
_PSH_C = $30
_EXC_C = $40
_INR_C = $50
_DCR_C = $60
_TST_C = $70
_DEC_C = $80
_HEX_C = $90
_ADD_C = $a0
_SUB_C = $b0
_MUL_C = $c0
_DIV_C = $d0
_MOD_C = $e0
_EXT_C = $f0
; common constants
; plus and minus 1 for increment and decrement
_PLS_1 = %00000100 ; i.e. the $04 part of $00000400
_MNS_1 = %11111100 ; i.e. the $FC part of $FFFFFC00
; masks for overflow and underflow
_MSK_O = %11000000 ; mask for overflow
_MSK_U = %11000000 ; mask for underflow - yes, the same!
#endif /* __COMMON_H */