mirror of
https://github.com/Russell-S-Harper/COMMON.git
synced 2024-11-16 01:11:33 +00:00
143 lines
4.5 KiB
C
143 lines
4.5 KiB
C
#ifndef __COMMON_H
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#define __COMMON_H
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; Using four byte quantities aabbccdd with sign bit, overflow/underflow bit, 20 bits significand, 10 bits
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; fraction. The quantity is valid if the overflow/underflow bit agrees with the sign bit. The intent is
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; to be able to recognize an overflow/underflow situation, rescale the arguments, and repeat the
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; calculation.
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; Largest value: $3fffffff or 1048575.999(9)
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; Smallest value: $c0000001 or -1048575.999(0)
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; Largest value for DEC: $3d08ffff or 999999.999(9)
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; Smallest value for DEC: $c2f70001 or -999999.999(0)
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; Instructions
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; SET r aabbcc.dd 1r dd cc bb aa Rr <- aabbccdd - set register
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; POP r 2r Rr <- RS - pop from stack
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; PSH r 3r RS <- Rr - push onto stack
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; EXC r 4r Rr <-> RS - exchange Rr with stack
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; INR r 5r Rr <- Rr + 1.0 - increment register
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; DCR r 6r Rr <- Rr - 1.0 - decrement register
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; TST r 7r F <- Rr <=> 0.0 - test register
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; DEC r 8r Rr <- dec(Rr) - convert Rr from hex aabbccdd to decimal #########
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; HEX r 9r Rr <- hex(Rr) - convert Rr from decimal ######### to hex aabbccdd
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; ADD r pq ar pq Rr <- Rp + Rq - addition
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; SUB r pq br pq Rr <- Rp - Rq - subtraction
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; MUL r pq cr pq Rr <- Rp * Rq - multiplication
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; DIV r pq dr pq Rr <- Rp / Rq - division
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; MOD r pq er pq Rr <- Rp % Rq - modulus
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; EXT z ... fz ... - system and user defined functions
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; ESC 00 - escape back into regular assembler
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; RTN 01 - return from subroutine
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; BRS xxyy 02 yy xx PC <- PC + xxyy - branch to subroutine
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; BRA xxyy 03 yy xx PC <- PC + xxyy - branch always
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; BRE xxyy 04 yy xx PC <- PC + xxyy - branch if Rp = Rq (after CMR)
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; BRG xxyy 05 yy xx PC <- PC + xxyy - branch if Rp > Rq (after CMR)
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; BRL xxyy 06 yy xx PC <- PC + xxyy - branch if Rp < Rq (after CMR)
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; BRZ xxyy 07 yy xx PC <- PC + xxyy - branch if Rr = 0.0 (after TST)
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; BRP xxyy 08 yy xx PC <- PC + xxyy - branch if Rr > 0.0 (after TST)
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; BRN xxyy 09 yy xx PC <- PC + xxyy - branch if Rr < 0.0 (after TST)
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; BRO xxyy 0a yy xx PC <- PC + xxyy - branch if overflow (after arithmetic operations)
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; BRU xxyy 0b yy xx PC <- PC + xxyy - branch if underflow (after arithmetic operations)
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; CPR pq 0c pq Rp <- Rq - copy register
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; LDI pq 0d pq Rp <- (int(Rq)) - load indirect from memory
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; SVI pq 0e pq (int(Rp)) <- Rq - save indirect to memory
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; CMR pq 0f pq F <- Rp <=> Rq - compare registers
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; 64 bytes in page zero for common registers
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_R0 = $C0
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_R1 = _R0 + 4
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_R2 = _R1 + 4
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_R3 = _R2 + 4
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_R4 = _R3 + 4
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_R5 = _R4 + 4
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_R6 = _R5 + 4
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_R7 = _R6 + 4
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_R8 = _R7 + 4
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_R9 = _R8 + 4
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_RA = _R9 + 4
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_RB = _RA + 4
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_RC = _RB + 4 ; workspace for arithmetic operations
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_RD = _RC + 4 ; as above and for EXC
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_RE = _RD + 4 ; register E maintains common status
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_RF = _RE + 4 ; register F saves/restores processor status
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; register E maintains common status
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; (dd cc bb aa) aa: index for register stack RS / ccbb: program counter PC / dd: flags F UONPZLGE
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_RSI = _RE ; register stack index
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_PCL = _RSI + 1 ; program counter low
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_PCH = _PCL + 1 ; program counter high
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_F = _PCH + 1 ; flags
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_PC = _PCL ; program counter
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; bits for flags
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_F_E = 1 ; if Rp = Rq (after CMP)
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_F_G = 2 ; if Rp > Rq (after CMP)
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_F_L = 4 ; if Rp < Rq (after CMP)
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_F_Z = 8 ; if Rr = 0.0 (after TST)
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_F_P = 16 ; if Rr > 0.0 (after TST)
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_F_N = 32 ; if Rr < 0.0 (after TST)
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_F_O = 64 ; if overflow (after arithmetic operations)
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_F_U = 128 ; if underflow (after arithmetic operations)
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; register F saves/restores processor status
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; (dd cc bb aa) aa: accumulator, bb: index X, cc: index Y, dd: processor status
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_ACC = _RF ; saved accumulator to restore
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_IDX = _ACC + 1 ; saved index X to restore
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_IDY = _IDX + 1 ; saved index Y to restore
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_PS = _IDY + 1 ; saved processor status to restore
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; 256 bytes of page two
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_RS = $200 ; register stack
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; 64 bytes of page three
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FN_FX = $300 ; list of system and user functions
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; function constants
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_ESC_C = $00
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_RTN_C = $01
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_BRS_C = $02
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_BRA_C = $03
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_BRE_C = $04
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_BRG_C = $05
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_BRL_C = $06
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_BRZ_C = $07
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_BRP_C = $08
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_BRN_C = $09
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_BRO_C = $0a
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_BRU_C = $0b
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_CPR_C = $0c
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_LDI_C = $0d
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_SVI_C = $0e
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_CMR_C = $0f
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_SET_C = $10
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_POP_C = $20
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_PSH_C = $30
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_EXC_C = $40
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_INR_C = $50
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_DCR_C = $60
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_TST_C = $70
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_DEC_C = $80
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_HEX_C = $90
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_ADD_C = $a0
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_SUB_C = $b0
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_MUL_C = $c0
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_DIV_C = $d0
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_MOD_C = $e0
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_EXT_C = $f0
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; common constants
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; plus and minus 1 for increment and decrement
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_PLS_1 = %00000100 ; i.e. the $04 part of $00000400
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_MNS_1 = %11111100 ; i.e. the $FC part of $FFFFFC00
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; masks for overflow and underflow
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_MSK_O = %11000000 ; mask for overflow
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_MSK_U = %11000000 ; mask for underflow - yes, the same!
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#endif /* __COMMON_H */
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