platform: add support for the EZ-Flash Parallel

arm9/source/patches/platform/ezp/ezpReadSectorsAsm.s

@@ -0,0 +1,83 @@
+.cpu arm7tdmi
+.section "ezp_readsectors", "ax"
+.syntax unified
+.thumb
+
+// r0 = src sector
+// r1 = dst
+// r2 = sector count
+.global ezp_readSectors
+.type ezp_readSectors, %function
+ezp_readSectors:
+    push {r4-r7,lr}
+
+    ldr r4, =0x040001A0
+    movs r3, #0x80
+    strb r3, [r4,#1]
+
+sector_loop:
+    // request sd read for sector 0xaabbccdd
+    // for xx number of sectors (up to 4 sectors)
+    // B9 00 00 xx aa bb cc dd
+    movs r3, #0xB9
+    str r3, [r4,#0x8]
+
+    // Maximum 4 sectors at a time.
+    // Check if 3 or lower first.
+    movs r7, #3
+    ands r7, r7, r2
+    bne sector_loop_skip_0_case // if between 1-3, then we can use value as is
+    movs r7, #4 // if AND returns 0, then it's a 4 sector read
+sector_loop_skip_0_case:
+    strb r7, [r4, #0xB]
+
+    lsrs r3, r0, #24
+    strb r3, [r4,#0xC]
+    lsrs r3, r0, #16
+    strb r3, [r4,#0xD]
+    lsrs r3, r0, #8
+    strb r3, [r4,#0xE]
+    strb r0, [r4,#0xF]
+
+    ldr r6, =0x04100010
+
+B9_poll_loop:
+    ldr r3, =0xA75860C8
+    str r3, [r4,#4]
+
+B9_poll_transfer_loop:
+    ldrb r3, [r4,#6]
+    lsrs r3, r3, #8
+    bcc B9_poll_check_transfer_end
+    ldr r5, [r6]
+
+B9_poll_check_transfer_end:
+    ldrb r3, [r4,#7]
+    lsrs r3, r3, #8
+    bcs B9_poll_transfer_loop
+
+    cmp r5, #0
+    bne B9_poll_loop
+
+    movs r3, r7
+    ldr r6, ezp_readSectors_readSdData_address
+    bl blx_r6
+
+    adds r0, r0, r7
+    subs r2, r2, r7
+    bne sector_loop
+
+    pop {r4-r7,pc}
+
+blx_r6:
+    bx r6
+
+.balign 4
+
+.global ezp_readSectors_readSdData_address
+ezp_readSectors_readSdData_address:
+    .word 0
+
+.pool
+
+.end