git.y1.nz

commit 6fce22f6747aca7cf3b3f49a2d9389cd1b4d3bc7
parent ce3c57764996907a754e3989b156e921b83b5783
Author: Toxa <untoxa@mail.ru>
Date:   Sat, 28 Aug 2021 21:36:44 +0300

SMS/GG: rand.h()/arand.s() port

Diffstat:
M
gbdk-lib/include/rand.h
27
+++++++++++++++++----------
M
gbdk-lib/libc/asm/z80/Makefile
1
+
A
gbdk-lib/libc/asm/z80/arand.s
89
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
gbdk-lib/libc/asm/z80/rand.s
48
++++++++++++++++++++++++++++++++++++++++++++++++

4 files changed, 155 insertions(+), 10 deletions(-)
diff --git a/gbdk-lib/include/rand.h b/gbdk-lib/include/rand.h
@@ -24,22 +24,25 @@
     again to re-initialize with the same or a different seed.
     @see rand(), randw()
 */
-void
-initrand(uint16_t seed) NONBANKED; /* Non-banked as called from asm in arand.s */
+#if defined(__PORT_gbz80)
+void initrand(uint16_t seed);
+#elif defined(__PORT_z80)
+void initrand(uint16_t seed) __z88dk_fastcall;
+#else
+#error Unrecognized port
+#endif
 
 /** Returns a random byte (8 bit) value.
 
     @ref initrand() should be used to initialize the random number generator before using rand()
  */
-int8_t
-rand(void);
+int8_t rand(void);
 
 /** Returns a random word (16 bit) value.
 
     @ref initrand() should be used to initialize the random number generator before using rand()
  */
-uint16_t
-randw(void);
+uint16_t randw(void);
 
 /** Random generator using the linear lagged additive method
 
@@ -50,14 +53,18 @@ randw(void);
 
     @see initrand() for suggestions about seed values, arand()
 */
-void
-initarand(uint16_t seed);
+#if defined(__PORT_gbz80)
+void initarand(uint16_t seed);
+#elif defined(__PORT_z80)
+void initarand(uint16_t seed) __z88dk_fastcall;
+#else
+#error Unrecognized port
+#endif
 
 /** Returns a random number generated with the linear lagged additive method.
 
     @ref initarand() should be used to initialize the random number generator before using arand()
  */
-int8_t
-arand(void);
+int8_t arand(void);
 
 #endif
diff --git a/gbdk-lib/libc/asm/z80/Makefile b/gbdk-lib/libc/asm/z80/Makefile
@@ -13,6 +13,7 @@ ASSRC = __strreverse.s strcpy.s strlen.s \
 	memcpy.s memmove.s \
 	setjmp.s \
 	abs.s \
+	rand.s arand.s \
 	__sdcc_call_hl.s __sdcc_call_iy.s \
 	atomic_flag_test_and_set.s __sdcc_critical.s \
 	crtenter.s 
diff --git a/gbdk-lib/libc/asm/z80/arand.s b/gbdk-lib/libc/asm/z80/arand.s
@@ -0,0 +1,89 @@
+        .module Random
+
+        .globl	.initrand
+        .globl	_rand
+
+        .area	_BSS
+.start_arand_vars:
+
+.randarr:
+        .ds	55
+.raxj:
+        .ds	0x01
+.raxk:
+        .ds	0x01
+        
+.end_arand_vars:
+
+        .area	_GSINIT
+
+        ld hl, #.start_arand_vars
+        ld de, #(.start_arand_vars + 1)
+        ld (hl), #0
+        ld bc, #(.end_arand_vars - .start_arand_vars)
+        ldir
+
+        .area	_CODE
+
+_arand::                        ; Banked
+        PUSH BC
+        LD D, #0
+        LD HL, #(.randarr - 1)
+        LD A, (.raxj)
+        LD E, A
+        DEC A		        ; Decrease the pointer
+        JR NZ, 1$
+        LD A, #55
+1$:
+        LD (.raxj), A
+        ADD HL, DE
+        LD B, (HL)
+
+        LD HL, #(.randarr - 1)  ; Ooh...
+        LD A, (.raxk)
+        LD E, A
+        DEC A                   ; Decrease the pointer
+        JR NZ, 2$
+        LD A, #55
+2$:
+        LD (.raxk), A
+        ADD HL, DE
+        LD A, (HL)
+
+        ADD B
+        LD (HL), A              ; Store new value
+
+        POP BC
+
+        LD H, #0
+        LD L, A
+
+        RET
+
+_initarand::                    ; Banked
+        CALL .initrand
+
+        LD A, #55
+        LD HL, #.randarr
+1$:
+        DEC A
+        LD (.raxj), A
+        LD B, H
+        LD C, L
+        CALL _rand
+        LD H, B
+        LD L, C
+
+        LD (HL), E
+        INC HL
+        
+        LD A, (.raxj)
+        CP #0
+        JP NZ, 1$
+
+        LD A, #24               ; Now the array has been filled,set the pointers
+        LD (.raxj), A
+        LD A, #55
+        LD (.raxk), A
+
+        RET
diff --git a/gbdk-lib/libc/asm/z80/rand.s b/gbdk-lib/libc/asm/z80/rand.s
@@ -0,0 +1,48 @@
+        .module Random
+
+        .area   _BSS
+
+.randval:
+        .ds     0x02
+
+        .area   _CODE
+
+_rand::	
+_randw::
+
+        ld HL, (.randval)
+        ex DE, HL
+        ld L, E
+
+        SLA L                   ; * 16
+        RLA
+        SLA L
+        RLA
+        SLA L
+        RLA
+        SLA L
+        RLA
+        LD H, A                 ; Save randhi*16
+
+        LD A, E                 ; Old randlo
+        ADD A, L                ; Add randlo*16
+        LD L, A                 ; Save randlo*17
+
+        LD A, H                 ; randhi*16
+        ADC A, D                ; Add old randhi
+        LD H, A                 ; Save randhi*17
+
+        LD A, L                 ; randlo*17
+        ADD A, #0x93
+        LD L, A
+        LD A, H                 ; randhi*17
+        ADC A, #0x5c
+        LD H, A
+        ld (.randval), HL
+
+        RET
+
+_initrand::                     ; Non banked
+.initrand::
+        ld (.randval), HL
+        ret

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