From ed7b9318bc9ac285250b117f87f47fe7f84af51b Mon Sep 17 00:00:00 2001 From: Christian Cunningham Date: Fri, 21 Jan 2022 12:55:57 -0700 Subject: Added scheduling logic --- include/globals.h | 1 + include/sys/schedule.h | 1 - src/globals.S | 3 +++ src/sys/schedule.S | 47 +++++++++++++++++++++++++++++++++++------------ src/sys/schedule.c | 2 ++ 5 files changed, 41 insertions(+), 13 deletions(-) diff --git a/include/globals.h b/include/globals.h index b33ebc7..16845d5 100644 --- a/include/globals.h +++ b/include/globals.h @@ -4,6 +4,7 @@ #include #ifndef GLOBALS_C +extern unsigned long irqlr; extern unsigned long cntfrq; extern unsigned long cmdidx; extern char cmd[2048]; diff --git a/include/sys/schedule.h b/include/sys/schedule.h index b153bdb..90e82dd 100644 --- a/include/sys/schedule.h +++ b/include/sys/schedule.h @@ -41,7 +41,6 @@ struct ThreadQueues { }; struct Scheduler { - void* sp; struct Thread* rthread; struct ThreadQueues thread_queues[PRIORITIES]; }; diff --git a/src/globals.S b/src/globals.S index 68101d7..3a5da83 100644 --- a/src/globals.S +++ b/src/globals.S @@ -1,4 +1,7 @@ .section ".bss" +.globl irqlr +irqlr: + .word 0 .globl cntfrq cntfrq: .word 0 diff --git a/src/sys/schedule.S b/src/sys/schedule.S index 298646a..4913034 100644 --- a/src/sys/schedule.S +++ b/src/sys/schedule.S @@ -1,26 +1,49 @@ .section ".text" .globl schedule - -// Implicit: SVC Mode .macro preserve_ctx cps #0x1f // Sys mode - push {r0-r12, lr} // Restore usr regs - cps #0x10 // Svc mode + // Store Usr regs + stmfd sp!, {r0-r12} + stmfd sp!, {lr} ldr r3, =scheduler // struct Scheduler - ldr r3, [r3, #4] // struct Thread* rthread - str lr, [r3, #0] // svc_lr -> void* pc + ldr r2, [r3, #0] // struct Thread* rthread + str lr, [r2, #0] // svc_lr -> void* pc + str sp, [r2, #4] // svc_lr -> void* sp + cps #0x10 // Svc mode .endm .macro restore_ctx ldr r3, =scheduler // struct Scheduler - ldr r3, [r3, #4] // struct Thread* rthread - ldr lr, [r3, #0] // void* pc -> lr_svc + ldr r2, [r3, #0] // struct Thread* rthread + ldr lr, [r2, #0] // void* pc -> lr_svc + ldr r0, [r2, #4] // void* sp -> r0 cps #0x1f // Sys mode - pop {r0-r12,lr} // Restore usr regs + mov sp, r0 // Set stack pointer + // Restore Usr regs + ldmfd sp!, {lr} + ldmfd sp!, {r0-r12} cps #0x10 // Svc mode .endm +// Assumption: Enter in SVC mode schedule: - //preserve_ctx - //restore_ctx - //bx lr + preserve_ctx + ldr r1, =irqlr + ldr r0, [r1] + cmp r0, #0 + beq 1f + // Replace LR with IRQ's LR + mov lr, r0 + // Clear IRQ's LR + mov r0, #0 + str r0, [r1] +1: + // bl get_next_thread // next_thread -> r0 + ldr r3, =scheduler + ldr r2, [r3, #0] // struct Thread* current + cmp r0, r2 // current = next? + beq 2f + str r0, [r3, #0] // next -> rthread +2: + restore_ctx + movs pc, lr diff --git a/src/sys/schedule.c b/src/sys/schedule.c index 96dc678..0dc89e9 100644 --- a/src/sys/schedule.c +++ b/src/sys/schedule.c @@ -1,3 +1,5 @@ void init_scheduler(void) { + // Set rthread to usrloopthread - an infinitely running thread so that the pointer will never be null + // Initialize Rotating Buffers } -- cgit v1.2.1