Refactorize RND label

Author: boriel

src/arch/zx48k/backend/runtime/random.py

@@ -5,8 +5,10 @@
 
 class RandomLabels:
     RANDOMIZE = f"{NAMESPACE}RANDOMIZE"
+    RND = f"{NAMESPACE}RND"
 
 
 REQUIRED_MODULES = {
     RandomLabels.RANDOMIZE: 'random.asm',
+    RandomLabels.RND: 'random.asm'
 }

src/arch/zx48k/translator.py

@@ -1268,8 +1268,7 @@ def visit_ABS(self, node):
         self.ic_abs(node.children[0].type_, node.t, node.children[0].t)
 
     def visit_RND(self, node):  # A special "ZEROARY" function with no parameters
-        self.ic_call('RND', Type.float_.size)
-        backend.REQUIRES.add('random.asm')
+        self.runtime_call(RuntimeLabel.RND, Type.float_.size)
 
     def visit_PEEK(self, node):
         self.ic_load(node.type_, node.t, '*' + str(node.children[0].t))

tests/functional/rnd.asm

@@ -0,0 +1,172 @@
+	org 32768
+__START_PROGRAM:
+	di
+	push ix
+	push iy
+	exx
+	push hl
+	exx
+	ld hl, 0
+	add hl, sp
+	ld (__CALL_BACK__), hl
+	ei
+	jp __MAIN_PROGRAM__
+__CALL_BACK__:
+	DEFW 0
+ZXBASIC_USER_DATA:
+	; Defines USER DATA Length in bytes
+ZXBASIC_USER_DATA_LEN EQU ZXBASIC_USER_DATA_END - ZXBASIC_USER_DATA
+	.__LABEL__.ZXBASIC_USER_DATA_LEN EQU ZXBASIC_USER_DATA_LEN
+	.__LABEL__.ZXBASIC_USER_DATA EQU ZXBASIC_USER_DATA
+_a:
+	DEFB 00, 00, 00, 00, 00
+ZXBASIC_USER_DATA_END:
+__MAIN_PROGRAM__:
+	ld de, 0
+	ld hl, 0
+	call RANDOMIZE
+	call RND
+	ld hl, _a
+	call __STOREF
+	ld hl, 0
+	ld b, h
+	ld c, l
+__END_PROGRAM:
+	di
+	ld hl, (__CALL_BACK__)
+	ld sp, hl
+	exx
+	pop hl
+	exx
+	pop iy
+	pop ix
+	ei
+	ret
+	;; --- end of user code ---
+#line 1 "/zxbasic/src/arch/zx48k/library-asm/random.asm"
+	; RANDOM functions
+RANDOMIZE:
+	    ; Randomize with 32 bit seed in DE HL
+	    ; if SEED = 0, calls ROM to take frames as seed
+	    PROC
+	    LOCAL TAKE_FRAMES
+	    LOCAL FRAMES
+	    ld a, h
+	    or l
+	    or d
+	    or e
+	    jr z, TAKE_FRAMES
+	    ld (RANDOM_SEED_LOW), hl
+	    ld (RANDOM_SEED_HIGH), de
+	    ret
+TAKE_FRAMES:
+	    ; Takes the seed from frames
+	    ld hl, (FRAMES)
+	    ld (RANDOM_SEED_LOW), hl
+	    ld hl, (FRAMES + 2)
+	    ld (RANDOM_SEED_HIGH), hl
+	    ret
+	FRAMES EQU    23672
+	    ENDP
+	RANDOM_SEED_HIGH EQU RAND+6 ; RANDOM seed, 16 higher bits
+	RANDOM_SEED_LOW  EQU 23670  ; RANDOM seed, 16 lower bits
+RAND:
+	    PROC
+	    LOCAL RAND_LOOP
+	    ld b, 4
+RAND_LOOP:
+	    ld  hl,(RANDOM_SEED_LOW)   ; xz -> yw
+	    ld  de,0C0DEh   ; yw -> zt
+	    ld  (RANDOM_SEED_LOW),de  ; x = y, z = w
+	    ld  a,e         ; w = w ^ ( w << 3 )
+	    add a,a
+	    add a,a
+	    add a,a
+	    xor e
+	    ld  e,a
+	    ld  a,h         ; t = x ^ (x << 1)
+	    add a,a
+	    xor h
+	    ld  d,a
+	    rra             ; t = t ^ (t >> 1) ^ w
+	    xor d
+	    xor e
+	    ld  d,l         ; y = z
+	    ld  e,a         ; w = t
+	    ld  (RANDOM_SEED_HIGH),de
+	    push af
+	    djnz RAND_LOOP
+	    pop de
+	    pop af
+	    ld e, a
+	    pop hl
+	    pop af
+	    ld l, a
+	    ret
+	    ENDP
+RND:
+	    ; Returns a FLOATING point integer
+	    ; using RAND as a mantissa
+	    PROC
+	    LOCAL RND_LOOP
+	    call RAND
+	    ; BC = HL since ZX BASIC uses ED CB A registers for FP
+	    ld b, h
+	    ld c, l
+	    ld a, e
+	    or d
+	    or c
+	    or b
+	    ret z   ; Returns 0 if BC=DE=0
+	    ; We already have a random 32 bit mantissa in ED CB
+	    ; From 0001h to FFFFh
+	    ld l, 81h    ; Exponent
+	    ; At this point we have [0 .. 1) FP number;
+	    ; Now we must shift mantissa left until highest bit goes into carry
+	    ld a, e ; Use A register for rotating E faster (using RLA instead of RL E)
+RND_LOOP:
+	    dec l
+	    sla b
+	    rl c
+	    rl d
+	    rla
+	    jp nc, RND_LOOP
+	    ; Now undo last mantissa left-shift once
+	    ccf ; Clears carry to insert a 0 bit back into mantissa -> positive FP number
+	    rra
+	    rr d
+	    rr c
+	    rr b
+	    ld e, a     ; E must have the highest byte
+	    ld a, l     ; exponent in A
+	    ret
+	    ENDP
+#line 23 "rnd.bas"
+#line 1 "/zxbasic/src/arch/zx48k/library-asm/storef.asm"
+__PISTOREF:	; Indect Stores a float (A, E, D, C, B) at location stored in memory, pointed by (IX + HL)
+			push de
+			ex de, hl	; DE <- HL
+			push ix
+			pop hl		; HL <- IX
+			add hl, de  ; HL <- IX + HL
+			pop de
+__ISTOREF:  ; Load address at hl, and stores A,E,D,C,B registers at that address. Modifies A' register
+	        ex af, af'
+			ld a, (hl)
+			inc hl
+			ld h, (hl)
+			ld l, a     ; HL = (HL)
+	        ex af, af'
+__STOREF:	; Stores the given FP number in A EDCB at address HL
+			ld (hl), a
+			inc hl
+			ld (hl), e
+			inc hl
+			ld (hl), d
+			inc hl
+			ld (hl), c
+			inc hl
+			ld (hl), b
+			ret
+#line 24 "rnd.bas"
+	END

tests/functional/rnd.bas

@@ -0,0 +1,4 @@
+
+RANDOMIZE
+a = RND
+